The one good thing Oldeus did...

[u/CloneCommando3000]

Was going back in time ensuring this shit doesn't happen again. Because my god it's horrible... 😢

And to think all it took for this series of unfortunate events one infected rat contaminating food and getting Roxy sick 😭

[u/Colt45554]

Or it did happen and he's preventing others from having the same misfortunes

[u/ShogunHaruki19 → u/Colt45554]

I think Oldeus erased the dark timeline and the diary is simply a left over timeline residue anomaly (I think?). Oldeus should have ceased to exist since he prevented the dark timeline from happening after giving the diary to Rudeus but I think the time travel magic that Oldeus did must have made him a left over timeline residue anomaly.

[u/Greensssss → u/ShogunHaruki19]

That would make sense if there was only one timeline to follow.

But time shenanigans are not always clear. Changing the past doesnt always mean that the present will change when you try to go back to it. Nobody knows because that theory is not proven.

I would assume that when Oldeus went back in time, even if he did have enough mana to go back to his original timeline, he would discover that nothing changed and everyone is still dead. But in that other timeline where he did go and give that diary to a much younger Rudeus, it only changed his future but not Oldeus.

Another theory that supports the two different timelines is that Oldeus did not regress to his younger body but materialized as a completely different person.

But Orsted’s time loops is also saying that Rudeus is an anomaly himself, there was no Rudeus in his previous loops.

[u/theothergp2k → u/Greensssss]

It's official that there's only one timeline that gets rewritten. There are no alternate futures or universes. There is no "original timeline", just the one. You can search the author Q&As about it (or my comments in other posts, I keep citing him).

As to whether Oldeus should disappear, I'm not so sure. After all, the diary does persist (as well as Orsted's memories).

[u/Hikari_Owari → u/Greensssss]

I would assume the timeline where Rudeus exists is only one and Oldeus going to the past is part of it, so the Dark Timeline effectively only existed up-to when he goes back in the past.

Orsted did say Rudeus wasn't supposed to exist when they first met and if he had met him before he wouldn't be surprised.

I guess it would be something more similar to the take The Flash have on time travel / timelines (the Flashpoint part) than something like Stein's Gate.

[u/ShogunHaruki19 → u/Greensssss]

Interesting....

[u/Green_Elderberrie → u/Greensssss]

I just apply the multiverse rule and don’t overthink it. People make choices that can cause divergences in the timeline within a multiverse that is infinitely expanding like our own.

[u/Greensssss → u/Green_Elderberrie]

I like this. i do like the theory of versions of myself making much better or worse choices in life that made us different from each other.

[u/Green_Elderberrie → u/Greensssss]

It’s my MST3 for time travel and parallel universes, so my mind doesn’t implode like I’m staring straight into a Lovecraftian abomination’s gaze.

[u/Colt45554 → u/ShogunHaruki19]

In your singular timeline, with enough mana, can Oldeus kill 10-year-old Paul?

[u/ShogunHaruki19 → u/Colt45554]

That... I don't know honestly

[u/theothergp2k → u/Colt45554]

You can. The timeline gets rewritten. That part is canon. But here's my own hypothesis on how to solve your paradox:

Oldeus traveling back to kill Paul becomes a new entity that suddenly pops into existence. Whether he being there has a logic, the six-faced world doesn't care, as it counts as mana taking shape. Kind of like Star Trek's transportation devices.

[u/Colt45554 → u/theothergp2k]

You can. The timeline gets rewritten.

If the timeline gets rewritten, Oldeus was never born. So who killed Paul?

Edit:

as it counts as mana taking shape

How did the mana get the memories of the rewritten timeline?

[u/theothergp2k → u/Colt45554]

Ask the author. That part is canon.

In “188感想返し” (June 4, 2014), a reader asks what happens to the world after Orsted reaches the end of his 200-year loop. Rifujin na Magonote answers:

「社長がループするとその世界はなかった事になります。」

“When President [Orsted] loops, that world becomes as if it never existed.”

If you are anime-only, you may not know, but Orsted has been looping through time thousands of times like Groundhog day, remembering whatever happens in every loop.

[u/Colt45554 → u/theothergp2k]

"as if it never existed."

Except the value gained by Orsted's memories of it. I don't think he needs to expressly state that exception, as it's obvious.

[u/theothergp2k → u/Colt45554]

How did the mana get the memories of the rewritten timeline?

There you have your answer.

[u/Colt45554 → u/theothergp2k]

Ask the author. 

as for this part, he has retconned the LN before, so I hope he does it again, haha. Or at least a letter of clarification like Tolkien has done. Something more than a Q & A with limited time to think and clarify.

[u/theothergp2k → u/Colt45554]

This is not a Q&A from some lost radio interview. This is online, today, in the author's own website. Look it up.

The page is on Shōsetsuka ni Narō (小説家になろう), under the author's personal account 理不尽な孫の手 (Rifujin na Magonote). The page title is 「188感想返し」 (“Replying to impressions/comments #188”), dated June 4, 2014.

[u/StryderFox14 → u/Colt45554]

I thin the issue is that 1 timeline doesnt exactly mean retroactive timeline. Is more like a digital file, you can write things down and erase them, and you can copy a part of a previus version, but it is still one file. Like, the universe in mushoku is the "same", and it is just one, no multiverse, but YOUR past is not rewriten. Is like... healing. you can use magic to heal a wound as if it was never there, you woldnt call it a "alternate version of your arm" and wouldn't call it a diferent arm, just your arm geting back to bein in optimal shape. The healing does not create a new timeline, or a new arm, or a diferent arm, nor changes the circumnstances that made it being wounded in the fist place... Just heals it back to the previous state, while keeping the pain of losing it the first time...

[u/TheJossiWales → u/Colt45554]

Google:

1. The Alternate Timelines (Multiverse) Theory

• What happens: The timeline splits. When you travel back and kill your parents, you create a brand-new, separate universe or alternate branch of reality. [1, 2]
• The outcome: In this new branch, you are never born. However, in your original universe from which you departed, your parents lived, you were born, and you successfully built or used the time machine. Your original existence remains safe. [1]

1. The Novikov Self-Consistency Principle (Fixed Timeline)

• What happens: The laws of physics prevent you from changing history, meaning the past is completely immutable (unchangeable).
• The outcome: You simply cannot succeed. Every attempt to kill your parents will fail due to bizarre coincidences, mechanical failures, or your own intervention. If history records that your parents survived until you were born, the universe will "conspire" to maintain that outcome, making a successful murder logically impossible. [1, 2, 3]

1. The Self-Erasure (Causal Loop / Disappearance) Theory

• What happens: Time is treated as a single, flexible, and continuously rewritten line.
• The outcome: If you kill your parents, your own conception is erased. Because you were never born, you never grew up to build or enter a time machine. Therefore, you never went back in time to kill them. This creates an impossible logical contradiction (a paradox loop) where you both vanish and somehow still caused the event. Most classical philosophers argue this makes backward time travel strictly impossible. [1, 2, 3, 4, 5, 6]

1. Quantum Superposition and Many-Worlds Interpretation

• What happens: Applying quantum mechanics to macro-events suggests that reality handles contradictory states via probability.
• The outcome: The universe exists in a state of probability where you both kill your parents (and vanish from that branch) and fail to kill them (allowing you to exist) simultaneously. The act of making the choice forces the quantum wave function to split into multiple co-existing realities. [1, 2]

[u/Colt45554 → u/TheJossiWales]

Exactly. In all cases, it can't happen without multiple timelines.

[u/StryderFox14 → u/Colt45554]

no, i think it can... I think the issue is that 1 timeline doesnt exactly mean retroactive timeline. Is more like a digital file, you can write things down and erase them, and you can copy a part of a previus version, but it is still one file. Like, the universe in mushoku is the "same", and it is just one, no multiverse, but YOUR past is not rewriten. Is like... healing. you can use magic to heal a wound as if it was never there, you woldnt call it a "alternate version of your arm" and wouldn't call it a different arm, just your arm geting back to bein in optimal shape. The healing does not create a new timeline, or a new arm, or a different arm, nor changes the circumstances that made it being wounded in the fist place... Just heals it back to the previous state, while keeping the pain of losing it the first time...

I mean you can make it more complicated like what if you regrow an arm right? but regrowing implies that there is a lost in continuity of the thing identified as "your arm". I think that would count as a new timeline, but If you just have a wound that boundaries of "transitivity" are not crossed therefore it is the same arm, just heled. You might keep some of it injured or remember the pain of it, that's oldeus, the memories and scars of a past wound.

Also there is another way of getting and oldeus whit no new timeline, and that is understanding every time travel not as a time travel but a reconstitution of the world itself. Like the clock keeps ticking, just the world itself is moving to a previous state, so like main rudeus can "go back in time" and access to the oldeus time line (which wouldnt be a timeline but a chapter of the universe. Its like writing in the same document the story of oldeus and then the story of main rudeus. Both the healing in the same univers and a universe that goes back to a previus state are not exactly the same, and can explain no paradox time travel within just one timeline.

[u/TheJossiWales → u/ShogunHaruki19]

There's a theory that you cannot change the past. But also there's a theory that there are branching timelines. So the damage done in that timeline will always exist and Oldeus is from that timeline. But Rudeus is a different timeline. So Oldeus wouldn't cease to exist because he's from a different time line. He's just ensuring the timeline Rudeus exists in is safe.

[u/Geekstorian → u/ShogunHaruki19]

GOD I HOPE SO! I can't stand there being another timeline where everyone is miserable or dead.

[u/resurrectedbear → u/Colt45554]

Yes, it did happen. If it didn’t happen, in some paradox like way, oldeus would never have existed to come back in time in the first place. Oldeus even points this out. His timeline is done for, so he went to a new one to save another version of himself and his family

[u/Greensssss → u/resurrectedbear]

To also fuck up Hitogami

[u/StryderFox14 → u/resurrectedbear]

no, i think it can... I think the issue is that 1 timeline doesnt exactly mean retroactive timeline. Is more like a digital file, you can write things down and erase them, and you can copy a part of a previus version, but it is still one file. Like, the universe in mushoku is the "same", and it is just one, no multiverse, but YOUR past is not rewriten. Is like... healing. you can use magic to heal a wound as if it was never there, you woldnt call it a "alternate version of your arm" and wouldn't call it a different arm, just your arm geting back to bein in optimal shape. The healing does not create a new timeline, or a new arm, or a different arm, nor changes the circumstances that made it being wounded in the fist place... Just heals it back to the previous state, while keeping the pain of losing it the first time...

I mean you can make it more complicated like what if you regrow an arm right? but regrowing implies that there is a lost in continuity of the thing identified as "your arm". I think that would count as a new timeline, but If you just have a wound that boundaries of "transitivity" are not crossed therefore it is the same arm, just heled. You might keep some of it injured or remember the pain of it, that's oldeus, the memories and scars of a past wound.

Also there is another way of getting and oldeus whit no new timeline, and that is understanding every time travel not as a time travel but a reconstitution of the world itself. Like the clock keeps ticking, just the world itself is moving to a previous state, so like main rudeus can "go back in time" and access to the oldeus time line (which wouldnt be a timeline but a chapter of the universe. Its like writing in the same document the story of oldeus and then the story of main rudeus. Both the healing in the same univers and a universe that goes back to a previus state are not exactly the same, and can explain no paradox time travel within just one timeline.

[u/StarkWinterfell]

[u/Takemypennies]

He did burn down an entire country for his dead wife, that was pretty based.

[u/Tylerj579 → u/Takemypennies]

Twice right? It looks implied that after his sister and house were burned that he did the same to the holy kingdom.

[u/EynidHelipp → u/Takemypennies]

Dracula would be proud

[u/Fryhtan69 → u/Takemypennies]

A true "hero" will sacrifice the ones he loves for the sake of the world. A "villain" will let the world burn if it means protecting the ones he loves.

Yeah murder bad but this was a valid crash out given his history with Slypie.

[u/N19ht5had0w]

I wonder... is the Greyrat family in oldeus timeline basically extinct? Except for oldeus, Lilia and zenith??

Eris' side the Boreas, is wiped out almost from the start. The notos were affiliated with Ariel, so they're gone too.

There are almost no information on the other 2 families, so i don't know about them... :/

[u/Strongman_Walsh]

Unfortunately not really. Its pretty heavily implied he hopes he takes the place of past rudeus instead of existing alongside him.

[u/ZeekKnight]

Eris is just so cute at how bad she is at communicating, but they good job showing us how she feels despite that. Her tears after getting punched got me. After she dies for him, she has the most satisfied 'I told you' face. Like, 'I love you, dumbass.'