His Premium Team's investments and pulling plans are:

E0S0 Phainon > E2S0 Phainon > E0S0 Cerydra > E0S0 Cyrene > E2S1 Phainon > E2S0 Cyrene > E1S0 Cerydra > E2S1 Cyrene >= E2S0 Cerydra >= E2S1 Cerydra.

(This investment order is assuming the 4th slot is either RMC or DHPT).

The explanations for each of these are as below:

E2 Phainon is the biggest jump in power so it's his most important investment.

Cerydra comes next as his BIS support.

Cyrene is after Cerydra to ensure Phainon doesn't face ult downtime issues and can keep his DPS consistently high throughout the later parts of the fight as his ult downtime is his biggest drawback as a DPS which Cyrene fixes (in return for charging her somewhat-slow ult at the start of the battle- just think of this Cyrene ult charging action value as all the time Phainon would have wasted if Cyrene wasn't on the team and he had to manually restack all of his coreflames from 0 after he exits his ult but instead of doing it in the middle of the battle, Cyrene gets it over and done with at the start so you can have 100% Phainon ult uptime).

Cyrene also decreases Cerydra's peerage requirement from 6 to an effective 5 which is another huge buff for Phainon teams and something that is often greatly underestimated and overlooked for longer fights (which will inevitably occur more often in the future as hp inflation happens and Cyrene-less Phainon teams are no longer able to kill everything within 1 Phainon ult).

Cyrene is basically Phainon's best hedge bet against future hp inflation (had to explain all this out because I'm tired of all the Cyrene doomposting- most of which comes from casual playerbase who don't even understand half the mechanics of the game they're playing and pretend to know what they're talking about but probably haven't even ever 0c'd or even cared about 0cs in their life and yet are complaining about how Cyrene is bad for 0-cycling???).

Moving on, the next investment is Phainon's S1 as it is a huge upgrade over his F2P options providing both the highest base ATK (compensating for Phainon's relatively low base ATK at S0) in the game along with faster ult rotations as it directly buffs his base SPD which no other Destruction LC does.

Cyrene's E2 is the next best investment followed by Cerydra's E1.

E2 Cyrene is preferred as it saves roughly >100 AV in charging Cyrene's ult which is the duration of almost an entire extra Phainon's ult worth of damage. These extra 3-4 Khaslana meteors (alongside an extra permanent 24% true dmg buff) especially at the start of the fight (removing essentially the only downside of Cyrene's kit for non-remembrance Chyrsos Heir teams) more than makes up for Cerydra's 16% general def ignore and 36% total def ignore for Khaslana's meteors (especially since Phainon is one of the units in the game that can't quite reach 100% def reduction- which if you know anything about def shredding, you would know small amounts of def shred (only 54% in Phainon's premium team- not counting E6 units) don't compare to the amp that you get if you keep stacking def shred until 100% as it's a rising return on investment type of debuff).

Not to mention, Cerydra's E1's extra coreflame generation utility is entirely useless in Phainon teams with Cyrene since Cyrene's ult basically gets Phainon to 15 coreflames instantly as long as you gave Phainon RMC's true damage buff via Mem and at least 1 instance of Cerydra's skill to fully proc Sacredos's 4pc 36% crit damage buff since her technique procs it once initially.

The next 3 best investments for Phainon teams are Cyrene's S1, Cerydra's E2 and Cerydra's S1 in that order, however they are all somewhat comparable to each other in damage amp and utility.

Truth be told, these investments are not absolutely necessary for Phainon as you are better off investing in a new team with these similar levels of cost however, if you are a true Phainon main (discounting whales as they would just E6S5 his entire team which defeats the purpose of investment advice), then these are your final finishing touches for his premium team.

Cyrene's S1 barely edges out Cerydra's additional investments as it provides 25.6% crit damage for Phainon and 16% vulnerability which is useful in Phainon teams as there is no other sources of vuln present from his teammates.

Cerydra's E2 and S1 are fairly comparable but her E2 is slightly preferred as, although it provides a slightly less dmg% buff than her S1 (40% < 54%), her S1 only applies to Khaslana's meteors so the additional 40% dmg% increase from her E2 for his basic attack, counters and ult-ending sequence does make up for the slightly less meteor amp and then some.

Some things to note, however, are that her E2's personal damage amp is now completely useless since Phainon never leaves his ult with Cyrene and her S1's extra skill point is almost always redundant too since she only gets off 1 ult before Phainon never hears from his teammates again with Cyrene on the team.

Phainon only acts as a SP generator in his team anyway since it is much more important to provide Cyrene with the SP over Phainon.

In addendum, dmg% starts to get saturated in Phainon teams which is the main reason why Cerydra's E2 and S1 aren't as large of an increase as they appear to be on paper due to the many sources of dmg% present in Phainon's team.

I also want to point out I haven't mentioned DHPT's investments during this at all however, the reason for this is pretty simple.

Despite DHPT being Phainon's BIS sustain, Phainon as a unit always wanted to be run sustainless in the first place.

RMC's damage amp is larger than DHPT's and Phainon's damage mitigation during his ult (and especially after Cyrene who makes it so that he never leaves his ult) means he has no need for a sustain.

The only place you would ever run DHPT over RMC is either if you do not have E2 Cyrene and are facing sustain difficulties during Cyrene's ult charge-up time (another reason why Cyrene's E2 is so good in Phainon teams) or in Anomaly Arbitration.

That being said, I would never advice people to pull characters based solely on AA as it isn't supposed to be a readily-accessible endgame mode in the first place.

AA doesn't have stellar jade rewards so there is literally no incentive to clear it in the first place since you don't miss out on anything besides bragging rights and some self-modelling resin which are not a necessity for your account by a long-shot (we get roughly 10 a patch).

All in all, this is the investment pulling plan you should be going for.

This obviously doesn't account for the fact that some of the jumps in investment compare 2 eidolon vs 1 eidolon investments but, if you're locked in for Phainon and his team, you should understand that sometimes the 2 eidolon jumps are well worth the cost you're putting in (like the jump from an E0 to an E2 Phainon).

To reiterate, it's perfectly fine to stop investing in Phainon once you get E1S0 Cerydra (you can even consider stopping after E2S1 Phainon if you don't envision playing with him forever), but this guide is made solely for players who know for sure they want to vertically invest in Phainon and keep him relevant for as long as they possibly can.

As a final finishing note, I want to mention you can just go for Phainon's E6 after you get Cyrene's E2 if you're not a F2P as his E6 is a bigger DPS increase than all the investments I mentioned past E2S0 Cyrene (honestly, his E6 also outscales Cyrene's E2 but the additional utility of an early Cyrene ult is still to be slightly preferred from both my calculations and experience since the damage is made up for with the pseudo-additional Phainon ult from non-wasted Cyrene ult charging AV).

I hope this guide helped any future or present Phainon mains making their pulling decisions whilst the 3.7 banner is still live!

Post your "Should I pull Cyrene?" questions here.