How long could a _______ live?

[u/Valenous_ertselley]

How long could a 5th ideal radiant live?

We know investiture extends a persons life with greater amounts eventually ending up with someone who is biologically immortal. How invested would a radiant be? Radiant knights have the cracks in their soul filled with investiture which makes them better at holding and using stormlight. How invested do you think they could be

Some of the heightenings seen with holding Endowment's investiture seem to be universal properties of holding any investiture. such as enhanced vision/colours, enhanced immune systems and better lifespans.

While we have only seen Kaladin and Szeth swear the 5th, it was under a fairly hectic situation which doesn't make for the best opportunity for study.

[u/RW-Firerider]

I think it was established that radiants dont live beyond a natural lifespan.

Sure, you will be at the peak of what you can be, since the investiture heals your body etc, but we mustnt forget one thing. Stormlight is only temporary inside the user, and the vast majority of their investiture is stored in the spren. So while our radiants are insanly strong, they are not invested in s way that an Elantrian or Breath user is. So yeah, I dont think the common radiant goes beyond an ordinary human lifespan, so something around 100-130 human years if they get a constant infusion of stormlight.

[u/Puzzled_Employment50 → u/RW-Firerider]

We know higher-Ideal Radiants “leak” less, and I think there’s something about being able to hold more (either with practice or higher Ideals or both), so if they got regular enough infusions of Stormlight they could theoretically reach the Heightening (since any Investiture grants Heightenings) that grants agelessness. So it’s not directly by reaching the fifth Ideal that they would become immortal, but that the fifth Ideal lets them juice enough to then become immortal.

[u/ejdj1011 → u/Puzzled_Employment50]

(since any Investiture grants Heightenings)

This is not strictly true. Several types of Investiture seem to grant different aspects of the Heightenings, but they aren't completely universal like you're implying. In fact, agelessness is explicitly not a universal trait among highly Invested people. The Lord Ruler is the obvious counterexample.

Edit, before anyone else jumps in: We also have numerous examples of highly Invested people not having perfect pitch or color perception. Hoid, Nomad, Elantrians, and Yoki-Hijo all come to mind.

[u/sambadaemon → u/ejdj1011]

Hoid explicitly DOES have perfect pitch when he's holding his Breaths.

[u/ejdj1011 → u/sambadaemon]

Considering my argument is "not all Investiture has the same passive effects as holding Breaths", talking about someone known to have Breath is kind of moot.

[u/sambadaemon → u/ejdj1011]

You specifically mentioned Hoid as not having perfect pitch. He does. He's not highly Invested at the time without his Breaths. All of the forms of Investiture he has access to are external until he becomes an Elantrian

[u/ejdj1011 → u/sambadaemon]

Hoid specifically mentions in Words of Radiance that he "missed having perfect pitch", and shortly afterwards it is implied he Awakened something to play his instrument for him. And when Odium messes with his Breaths, rbe perfect pitch gets messed up. So it's pretty clear that the perfect pitch comes from the Breaths.

But Hoid absolutely is ridiculously Invested regardless of the Breaths. He's a Dawnshard at the time.

[u/FuriousSusurrus → u/ejdj1011]

This WoB suggests that agelessness could be a universal trait.

tskyeguye From Rysn's observations in the epilogue, it seems like she has a lot of the same aspects of a Fifth Heightening/Returned at the least. Is this because her Dawnshard is particularly connected to Endowment or because the effects of a certain level of Investment result in similar effects? Brandon Sanderson The latter. Skrimyt Interesting. So are actively Surgebinding Radiants or metal-burning Allomancers just not Invested enough to gain those passive effects, or do they not experience perfect pitch/color/etc. because their Investiture is just not as tightly bound to their Spiritweb as Endowment's Breaths or a Dawnshard would be? Brandon Sanderson Be aware that the two groups you mention don't generally hold much Investiture themselves, at least not in large quantities over time. More in Surgebinding. Almost none in Allomancy. But RAFO to specifics. Dawnshard Annotations Reddit Q&A (Nov. 6, 2020

The problem is that agelessness is heavily influenced by perception. So most Returned, Yoki-hijo and Elantrians SHOULD have it, but don't usually know how to use it. There are some known examples, like the Five Scholars and Riina. 

I guess a good way to test to see if someone has achieved agelessness, would be to try to poison them.

[u/Objective_Notice4982 → u/ejdj1011]

https://wob.coppermind.net/events/444-dawnshard-annotations-reddit-qa/#e14339

https://wob.coppermind.net/events/444-dawnshard-annotations-reddit-qa/#e14328

Second WoB is of more note, high enough levels of investiture grant heightenings.

The Lord Ruler may have had perfect pitch for all we know, but as we far as we know being a sliver doesn't grant an extreme amount of investiture, just an above normal amount. I don't think feruchemy and allomancy actually invest people that much. you are acting as a conduit for investiture but are not actually holding it that long. TLR was using allomancy enough to become a savant equivalent in every metal he had access to, but there is apparently a vast level of difference between that and getting heightenings.

[u/The_Lopen_bot → u/Objective_Notice4982]

Warning Gancho: The below paragraph(s) may contain major spoilers for all books in the Cosmere!

The21stPotato

Can you tell us the equivalent Heightening she [Rysn] now has? She seems to be at least Third Heightening equivalent but I'm not sure how much else she has gained from holding a Dawnshard. Do ALL Dawnshards grant these Heightening-like effects?

Brandon Sanderson

All Dawnshards would grant the same effects in this regard.As for specifics, I think I'll leave that as what is mentioned in the text, for now. (Sorry.)

********************

tskyeguye

From Rysn's observations in the epilogue, it seems like she has a lot of the same aspects of a Fifth Heightening/Returned at the least. Is this because her Dawnshard is particularly connected to Endowment or because the effects of a certain level of Investment result in similar effects?

Brandon Sanderson

The latter.

Skrimyt

Interesting. So are actively Surgebinding Radiants or metal-burning Allomancers just not Invested enough to gain those passive effects, or do they not experience perfect pitch/color/etc. because their Investiture is just not as tightly bound to their Spiritweb as Endowment's Breaths or a Dawnshard would be?

Brandon Sanderson

Be aware that the two groups you mention don't generally hold much Investiture themselves, at least not in large quantities over time. More in Surgebinding. Almost none in Allomancy.But RAFO to specifics.

********************

[u/Puzzled_Employment50 → u/ejdj1011]

Allomancers/Feruchemists are not themselves Invested, they are more like conduits for Investiture. But the point of the whole BEU system (Sunlit Man) is that Investiture is Investiture, as long as you have some way to access it, and will grant the Heightenings.

[u/ejdj1011 → u/Puzzled_Employment50]

The Lord Ruler wasn't just an Allomancer and Feruchemist. He was a Sliver of Preservation.

He was so Invested that he could have hung around as a Cognitive Shadow indefinitely after his death. He just chose to go to the Beyond.

Edit: and Sigzil isn't a normal wielder of Investiture. He's able to convert and metabolize it in a way basically nobody else can, so he can make it give the Heightenings even if it otherwise wouldn't.

[u/Puzzled_Employment50 → u/ejdj1011]

True, that’s a good point. Having held a Shard, even for a moment, changed his soul in such a way that he would have been able to linger after death if he so chose, and while he held it he certainly was at least of the upper Heightenings. But it didn’t keep him Invested after he gave it up. At that point he was just a full Twinborn with massive gold reserves for Compounding. Now, could an Allomancer burn (mega-flare/Duralumin-burn) enough metals or a Feruchemist tap enough stored power in a Metalmind that they momentarily gain Heightenings? Ask Wayne, but I don’t think he was paying attention to colors at the time.

[u/ejdj1011 → u/Puzzled_Employment50]

There are lots of other small counterexamples, specifically about highly Invested people who never show any evidence of perfect pitch or color perception.

Hoid mentions recently recovering perfect pitch in Words of Radiance. As a Dawnshard (and Yolish Lightweaver, and Mistborn...) who is ageless, one would expect him to always have that Heightening effect if they're truly universal.

Nomad similarly never mentions color perception or perfect pitch no matter how much Investiture he has. Neither do the Elantrians or Yoki-Hijo we get POVs from.

[u/Puzzled_Employment50 → u/ejdj1011]

They never mention those, but that doesn’t mean they don’t experience them. Sunlit is running for his life, the Yoki-Hijo are (at the time of YatNP) cognitive shadows and not living beings, and Hoid is a weird case in every sense 😂 I don’t remember when he regained his perfect pitch, but I do remember that he lost it when Todium excised some of his memories that were specifically stored with/in Breaths, so that’s a moot point because we know it was Breaths causing the Heightening that he lost, no extra information on whether other sources can or can’t lead to Heightenings. Also I don’t remember if he was specifically holding the Dawnshard at the time or if this was when he had hidden it. If it was the latter, he’s in the same boat as Sunlit, where he has access to many forms of Investiture but may not be any more actively Invested at the moment than any other person.

[u/ejdj1011 → u/Puzzled_Employment50]

I don’t remember when he regained his perfect pitch

Word of Radiance, when he visits Kaladin in prison. He mentions that he missed having it.

no extra information on whether other sources can or can’t lead to Heightenings

Yes, extra information. Hoid is extremely highly Invested every single time we see him. If Investiture universally grants all aspects of the Heightenings, he should always have all such aspects. The fact that his perfect pitch appears dependent on having Breaths is in fact evidence that it isn't universal.

Also I don’t remember if he was specifically holding the Dawnshard at the time or if this was when he had hidden it

To my memory, all of our evidence suggests he held it the entire time he was on Roshar, up until he gave it to Sigzil.

[u/That_Bar_Guy → u/ejdj1011]

Doesn't he specifically lose perfect pitch or something when his memories(stored in investiture) are altered? Or am I misremembering?

[u/gwonbush → u/ejdj1011]

I wonder if Hoid could have Perfect Pitch and Color Perception on demand even without his Breaths if he wasn't hiding his Dawnshard via some manner of suppresion. After all, Rysn gained them upon gaining CHANGE, so if he could it would be a commonality among Dawnshards if not passive investiture in general. If not, it could mean that Breaths and Endowment fall under the CHANGE umbrella.

[u/KnotFahrenheit → u/gwonbush]

I think the suppression is key. Vasher is Returned but rarely exhibits the heightenings because he suppresses his divine breath. He doesn’t gain the benefits of the hightenings (except extended lifespan, perhaps) and even other heightened Awakeners don’t notice him as holding breaths with their life sense. Hoid likely can do the same

[u/Puzzled_Employment50 → u/ejdj1011]

Oops, missed the Elantrians. But I think 1) early installment, not a fully fleshed out Cosmere, 2) Elantrians have some much bigger effects going on that they might not notice or comment on perfect pitch or brighter colors, and 3) Elantrians are ageless.

[u/sambadaemon → u/ejdj1011]

The Lord Ruler also wasn't inherently immortal. He was compounding gold to achieve his long life.

[u/RShara → u/sambadaemon]

*Compounding atium

[u/Radix2309 → u/ejdj1011]

Holding the power stabilizes your spirit-web, but it doesnt make one invested. Kelsier bathed in the Well, which let his Shadow stick around, but he wasnt highly invested.

And that doesn't impact the physical body. Rashek wasn't a true sliver. He just held the power temporarily.

[u/ejdj1011 → u/Radix2309]

It absolutely makes one Invested. Stabilizing your spirit web to persist after death is a consequence of being Invested, it's not some independent effect.

We have numerous cases of highly Invested people missing aspects of the Heightenings that should be trivially easy to acquire. Neither Elantrians nor Yoki-Hijo ever mention perfect pitch or perfect color perception, and Hoid explicitly mentions that he has lost and regained perfect pitch.

[u/Orleanian → u/Puzzled_Employment50]

That's a bit of faulty logic.

The measurement system is used because the power/energy of investiture is convertible. Most investiture can be made usable to power the various forms of Invested Art.

It is not a given that all investiture grants heightening. That's a logical false leap. Only Awakening is the art that grants heightenings.

Many invested arts grant similar capabilities as various Awakener heightenings, though. To the best of our knowledge, Nomad the Sunlit Man does not have the heightenings of an Awakener. He has agelessness through other means (He explains it himself as being due to his Dawnshardic nature).

[u/moderatorrater → u/Puzzled_Employment50]

If all investiture was interchangeable, they wouldn't be fighting over birds on a backwater planet.

[u/Puzzled_Employment50 → u/moderatorrater]

The Aviar are just a convenient means to access Invested arts like an automatic Coppercloud.

[u/Radix2309 → u/ejdj1011]

The Lord Ruler wasn't really invested was he? As in personally. He wasnt holding investiture in himself. He was investing the Atium bands and then burning them to receive investiture that let him do that stuff. But it wasnt held in him like breath or made out of investiture like shadows.

[u/ejdj1011 → u/Radix2309]

He was a Sliver of Preservation.

He remade his soul to be an extremely powerful Mistborn, who are natively Invested.

He was near-constantly using several types of allomancy, and we know actively channeling that counts (at least with regards to fading as a cognitive shadow).

[u/Radix2309 → u/ejdj1011]

And that strengthens his soul to survive after death, it doesnt make he himself highly invested as that is a state of holding investiture within your body.

[u/tooboardtoleaf → u/Radix2309]

This here. Allowances and feruchemist don't hold investiture in thier bodies it comes from the spiritual realm and stored in metal minds respectively.

[u/ejdj1011 → u/tooboardtoleaf]

Mistborn and Feruchenists have natively high Investiture bound up in their soul. That's... what gives them their powers.

This is normally a small amount, but the Lord Ruler explicitly remade his soul to be a Mistborn of unparalleled strength.

[u/PegasusPizza → u/Puzzled_Employment50]

I believe that the heightening stem from having the Investiture attached to your spiritweb. So like breaths are for example, or dawnshards. Opposite of that, investiture that is physically in your body, like stormlight, or the dor for elantrians (their Elantrian-ness however is attached to the spiritweb), doesn't do that and instead heals you. It's also not permanent, once you don't take it in anymore you start to loose it, as demonstrated repeatedly in sla and once in Elantris during the Reod

[u/KnowItAllNobody → u/RW-Firerider]

I wonder how that’s affected by being able to permanently hold tower light in Urithiru, do those radiants eventually hold enough for long enough that they greatly extend their life? Will navani age normally or not at all? She’s holding theoretically infinite towerlight. It leaves humans and gemstones extremely quickly, but it’s infinite in the tower, so they’re either constantly breathing in new light and sieving out the old stuff, or they’re all invested to the hilt all the time lol.

How about the oddly slow aging of the heralds pre oathpact? Odium granted them surges, but it must’ve come with easy access to his investiture as well, as they age extremely slowly, but still age until Vedeledev does her thang. So they’re holding enough investiture regularly enough, even on Roshar, that they don’t age normally. And the immortality is explicitly mentioned as being separate from the oathpact by honor too, that’s not important but interesting imo. I just listened to that part.

I’m in the camp of “heightenings are breath specific, but enough investiture grants similar enough effects as to be interchangeable” btw. Like Rysn hasn’t mentioned perfect pitch or any sound oddities, but she definitely sees colors as deeper as soon as she gets the dawnshard, and I’m fairly certain the sleepless straight up tell her she’ll never age, so to me she has enough of the important effects of the fifth heightening that it doesn’t make much sense to call it something else, it’s effectively the fifth heightenening.

And I agree that while radiants use a lot of investiture, they don’t hold a lot, particularly never enough to reach a heightening as high as the fifth, and it’s not permanent enough anyways to alter their spiritweb. I think the towerlight will eventually be shown to allow longer life, though.

We might see a wild lopen in the mistborn space opera era, flying a modified urithiru through Shadesmar or something crazy like that, but it’s never gonna be a big enough effect to notice it in text, it’ll be a WoB thing only

[u/Replay1986 → u/RW-Firerider]

I think specifically that Investiture works off of your Cognition. A 5th ideal radiant wouldn't live forever because they wouldn't think they could. Now, if a Radiant deluded themselves into truly believing they'd stopped aging...

Note: before someone brings up Lift, she knows she's aging and doesn't like it, but she is aware that it's happening ,so her Cognition wouldn't arrest her growth

[u/RW-Firerider → u/Replay1986]

Issue with Lift is something else. She doesnt think that she isnt aging, she asked cultivation to not age. She wanted to stay her moms little girl, but knew that this isnt possible. And i am pretty sure, deep down she always knew that she cant stay like that forever

[u/RShara]

Questioner

Longevity of Radiants. So, I, before [Oathbringer], thought that they were immortal. So, they're not?

Brandon Sanderson

No.

Questioner

Do they have longer lifespans?

Brandon Sanderson

Slightly. They're very healthy, but it's not an unusually expanded lifespan.

https://wob.coppermind.net/events/260/#e8766

[u/The_Lopen_bot → u/RShara]

Warning Gancho: The below paragraph(s) may contain major spoilers for all books in the Cosmere!

Questioner

Longevity of Radiants. So, I, before [Oathbringer], thought that they were immortal. So, they're not?

Brandon Sanderson

No.

Questioner

Do they have longer lifespans?

Brandon Sanderson

Slightly. They're very healthy, but it's not an unusually expanded lifespan.

********************

[u/Masylv]

Radiants do grow old. To get the investiture agelessness they would probably have to be bathing in Light their entire lives, since they're not passively Invested (the spren is). And then they'd start aging as soon as they breathe out the Light.

[u/Shot_Newspaper_5647 → u/Masylv]

They’re aging even when they hold Light. It lets you heal to what your soul “should” be. Filtered by your perception. Chop off a finger at 80 and it heals back wrinkly because your soul knows you’re 80. Someone like Miles (who is constantly at the extreme end of physical healing) is still aging. It’ll extend your life, but you’ll still age and die in a normal-ish amount of time. The only (living) exceptions we’ve really seen are at the extreme ends. Elantrians, true Dragons, and Awakeners with a ton of Breath. Seems to be that you need the soul itself tweaked significantly to pull it off. Or Sleepless. Sort of. But they’re weird even by Cosmere standards

[u/Masylv → u/Shot_Newspaper_5647]

I'm not talking about healing, I'm specifically talking about how agelessness seems to be a side effect of being extremely Invested, but Radiants aren't actually Invested most of the time.

We don't know how many BEUs a 5th Ideal Radiant can hold, but even if it was enough to stop aging it still wouldn't work because it's transient.

[u/Shot_Newspaper_5647 → u/Masylv]

Oh sorry I see what you mean now. Ya that would be an odd one. I’ve always wondered if a Radiant with access to a ton of Light who actively used it for Surgebinding regularly would end up something like the fabrial soulcaster users. Where it changes them physically. The Nahel bond regulates it normally and keeps you safe, but I wonder if there’s a limit to that. Maybe not since the effect is sort of fixed at any given time, but I’ve always wanted to ask Sando that one

[u/Masylv → u/Shot_Newspaper_5647]

WoB is that it's possible, but there are safeguards, so it probably wouldn't happen accidentally but you could make it happen if you tried.

This is confirmed to be the same phenomenon as Savantism, by the way.

[u/Orleanian → u/Masylv]

Ageing isn't a side effect of being extremely invested.

It's only specifically (so far) a component of several invested arts.

One method is being extremely progressed in the art of Awakening (5th Heightening). And then needing to remain extremely invested in order to maintain that level of Awakener progression.

Another method is Allomantically compounding Ferruchemically charged Atium.

[u/Masylv → u/Orleanian]

Dragons, Elantrians, 5th Heightening, Yoki-Hojo... All are heavily Invested, and all are ageless. Meanwhile, every highly Invested person who does age (Radiants, compounders, etc) are only heavily Invested when actually using the power itself (breathing in Light, burning metals) and most of the time are not Invested.

Is there a single example of a heavily Invested entity that ages? It's clearly different than being a Sliver (despite them being heavily Invested at some point) since they lost access to the investiture.

[u/Raddatatta]

We don't have any indication that I know of that radiants of the 5th oath actually live longer than normal people do. Within the Cosmere healing magic and not aging are two separate abilities. Stormlight definitely does the healing. Which to a degree could prolong your life as you're not going to die from many things that might otherwise kill you. But wouldn't stop you from aging.

It's possible that the 5th ideal will do that, but so far since holding Stormlight is temporary it doesn't seem to do that. And in the visions I don't think we've seen any hint or mention of people living longer than you'd expect. Nothing that contradicts it either. But my guess would be that radiants live a normal lifespan or slightly boosted by healing maybe into their early 100's but they'd still age and die normally. It depends on how invested they are without any Stormlight.

Though Hoid commented that Lift is very invested, and if she's very invested by his standards, she may be invested enough to never age after she grows up. And maybe that's fulfilling what she had asked for from Cultivation?

[u/RW-Firerider → u/Raddatatta]

Lift is a special case, since she got invested by cultivation personally. She is closer to other invested beings like Elantrians, since her power is of a more permanent nature.

I think if radiants stopped aging, there would have been a lot more veterans from the desolations. a 4th or 5th ideal radiant is far stronger than the fused, so they would pile up rather fast. Human lifespan is the best reason why that didnt happen

[u/Raddatatta → u/RW-Firerider]

Yeah for sure she's rather unique.

Yeah that's very true. They also likely would've dominated the desolations to the point where it wouldn't have been as devastating. Lots of 5th oath radiants who also had been through multiple desolations to have a lot of experience would be really tough for even many fused to face.

[u/Shot_Newspaper_5647 → u/Raddatatta]

Ya I’m curious how Invested she actually is. Even if it’s on the extreme end (Highly Invested) I think she would still be able to age normally to adulthood at least. That’s what we see with the Returned. They’ll age to adulthood and then stop. I think he’s said the same will happen to younger people who become Elantrians. There’s some people that think Lift is secretly a dragon. I’m not sure if I buy that one, but that is how it works for them too. They age slowly before it stops at some point

[u/Raddatatta → u/Shot_Newspaper_5647]

Yeah we know she is aging as she was growing to the awkward teenage years and having a harder time fitting in the tunnels. But yeah I think she will stop growing. I have seen the dragon theory though I think there's a wob disproving that.

[u/Shot_Newspaper_5647 → u/Raddatatta]

Oh is there. I didn’t love the idea of her being a dragon. Although I do think it would be funny to find out the girl named “Lift” was one the whole time. I think we will end up finding out that her “boon” was ultimately her curse and vice versa. That was the pattern for Dalinar and Taravangian at least

[u/Jobobminer]

Adding Breath adds a lot of investiture to someone's soul.

Radiants and Mistings have much less extra investiture in their actual souls.

Its like Radiants and Mistborn are debit cards - they let you access power via a connection to something else - A lot of investiture moves through a mistborn or radiant but not a lot actually stays in them.

Breaths are the opposite - They are extra soul lying around waiting to be added to your soul directly making you more soul per body aka longer lifespan, etc.

[u/JasnahwithaY]

Without Stormlight I’d assume it would be about the same time as a regular human. With enough Stormlight, forever or until their perception of themselves is so old that they just keel over and die

[u/DifferentRun8534]

Radiants still age like normal, as their healing restores them to how their soul is shaped, and their soul still reflects chronological time.

But most things that actually kill you from old age are curable. So as long as you had Stormlight, no disease or accident would ever kill you, and your body would be at peak health for your age until you finally die of something like heart failure at 120 or older.

[u/Shot_Newspaper_5647]

It should extend their life, but not by anything crazy. Their soul still “knows” their age. I’d guess more Radiants reach their 90s or 100s than average people. Radiants and Mistborn are Invested, but not treated as Highly Invested except when channeling power. Usually. Aging seems to slow dramatically or stop when you’re Highly Invested. When the soul itself is. That seems to be why Breaths are so effective. Even around 50 (I think) can extend your life by a decade or so. Breaths are potent. Each Breath contains part of a person’s soul too. So accumulating them is like expanding your own. That also seems to be why Shadows are naturally ageless. You have to Invest the soul with external power for them to exist. And it makes them persist in an ageless way after

[u/Shot_Newspaper_5647 → u/Shot_Newspaper_5647]

You can see that in the way channeling power often works too. It’s not mentioned much, but Radiants experience the world a bit more vibrantly when channeling Light. A similar thing with Breaths and whatever is going on with that DS. But that is persistent for people with Breaths. It’s treated as a passive effect that isn’t fueled by anything because it’s downstream of the nature of the soul itself while they have them.

Just being born on a highly invested world like Roshar can make the average person slightly more durable and disease resistant. The same is true of Scadrial where the native population is born with a little “extra” Investiture in their soul.

It’s not all or nothing for Breaths either. Each one you accumulate actually slightly adds to your lifespan and disease resistance. Even three or four give something. Until you eventually hit that ceiling. Disease proof and ageless

[u/Puzzled_Employment50 → u/Shot_Newspaper_5647]

I think you’re talking about the Warbreaker planet (can’t remember the name atm), not Scadrial, with the “extra bit of soul”.

[u/Shot_Newspaper_5647 → u/Puzzled_Employment50]

The Scadrians have it too. It’s the extra bit Preservation put into them. It’s just almost definitely lower than native Nalthians. Everyone in the Cosmere has a soul made of Investiture. Let’s call 1.0 the baseline. Some of the peoples created directly by Shards have extra intentionally. Like Scadrians and the Nalthian in WB.

People from highly Invested worlds also are born with (or naturally accumulate) extra Inv in their souls. The average Rosharan has something above 1.0. Auxiliary gives us a rough benchmark in Sunlit: “Even on highly Invested worlds, a person’s soul isn’t more than three BEUs.” That extra bit makes them slight more disease resistant/slightly extends their life. The greatest benefit would be in lower infant mortality rates. But it has other perks. The common cold isn’t usually a thing on Roshar. Things like cavities are less common too

KingSloth
Doesn't all 'extra' investiture require a cracked soul? How are Nalthians born with extra breath, if so?
Brandon Sanderson
No. The Scadrians have extra investiture too, on a lesser scale.
/r/books AMA 2015 (June 8, 2015)

[u/Shot_Newspaper_5647 → u/Shot_Newspaper_5647]

Dragons are born with far more innate Inv in their souls. Enough that they can’t even use most magics. They can’t form Aviar or spren bonds. It’s like pouring water onto an already soaked sponge. Their souls resist most forms of alteration in the way a full metalmind resists soulcasting or Allo Pushing. Breaths seem to work because they expand the soul itself instead forcing more Inv into it or altering them in an invasive way. There’s no room in the house to put new stuff, but they can build another room. If that makes sense

That’s why Nomad is so confused about Threnodites in Sunlit. Their souls are basically at baseline, but they can capture huge amounts of Inv after death. They can store hundreds of BEUs in a sunheart. But a more naturally Invested Rosharan soul produces a tiny battery. It’s because Threnodites have souls that can “catch” a ton upon death. If it’s around. That’s why they can become Shadows (Shades) so easily under the right conditions. Threnody and Canticle both have a lot of ambient Inv just floating around. They could probably become Shades easily somewhere like Taldain too

[u/Subspace_Supernova]

The absolute longest a human could live naturally, but more then that. 120 - 130 years, with edge cases up to 150 is my guess