Honkai: Star RailCerydraBest build, teams and other guides

[Overview]

Cerydra is a Harmony support character. She is a lot more niche than most Harmony units, specialising in buffing and improving an ally's Skill and Skill DMG. Her Skill provides a flat SPD buff to herself and a target ally, and will start gaining charges. When the buffed ally has reaches max stacks, their next Skill will be used a second time for free at max strength. For DPS characters that specialise in Skill DMG, Cerydra can be a powerful upgrade; outside of this niche, Cerydra is much less useful.

[Intro]

Morally ambiguous, yet certainly ambitious, Cerydra is a commanding presence. She is a kind of Harmony character that we haven't seen in quite a while, one who very clearly caters to a specific method of dealing damage more exclusively than most others.

Cerydra is very clearly designed with one or two rather legendary DPS characters in mind, and this is quite apparent through the way that her kit works; it's a very strong kit, don't get me wrong, but the criteria to make full use of it is quite challenging to meet.

[Skill]

The most impactful part of Cerydra's kit. Cerydra grants one ally character the Military Merit buff. This is a charging status that can hold up to 8 Charge. Cerydra immediately gains 1 point of Charge upon using this Skill, and will gain 1 more Charge if she uses it on the same ally again.

When allies with this buff reach at least 6 points of Charge, their Military Merit is upgraded into Peerage, immediately dispelling any Crowd Control debuffs.

Peerage retains the benefits of Military Merit, but additionally increases the buffed character's Skill CRIT DMG by 72%, and also grants 10% All-Type RES PEN. Peerage will also automatically trigger a Coup de Main when the buffed ally uses their Skill on enemy targets.

Coup de Main will copy the Skill about to be used, and use it before the actual Skill. The character's Skill is then used afterwards as normal, and this appears as having two Extra Actions in the Turn Order. This will cause the copied Skill to retain its full power, as it won't consume ally resources or Skill Points (and then the normal Skill that happens immediately after will consume things as normal). Peerage will end after the Coup de Main attack and revert back into Military Merit, consuming 6 points of Charge in the process.

This is naturally very potent for Skill-based damage dealers, though there are some caveats to note that can crop up depending on the exact team comp and encounter you’re in. Finnicky, but doubling up on a powerful Skill is already worth a tremendous amount for some.

[Talent]

This describes Military Merit and further acquisition of Charge. The character that has Military Merit will gain an ATK boost equal to 24% of Cerydra's ATK. This can be a pretty substantial ATK increase provided that Cerydra is built for ATK (she should be).

Whenever the character with Military Merit uses their Basic ATK or Skill, Cerydra gains 1 point of Charge, though this is turned off during the ally's Coup de Main attack.

In addition to this, any attack that the ally with Military Merit uses will also cause Cerydra to deal 1 instance of Wind Additional DMG, equal to 60% of her ATK. Strangely, this has a use limit of 20 times, which will be reset upon using her Ultimate.

The additional DMG is really not very impressive at all compared to the benefits from her Skill's overall buffing effects. Cerydra also cannot transfer Charged up Military Merit from character to character; using her Skill on a new ally will reset the Charge to 0.

[Ultimate]

Cerydra launches an attack against all enemies, dealing 240% ATK. She also gains 2 points of Charge upon using this, and in the event that no ally character has Military Merit, will automatically grant the first deployed character the Military Merit buff.

This will mostly be used for the 2 points of Charge it gives, rather than the damage of the ability. The Energy cost of 130 is a little above average.

[Technique]

Actually somewhat important for Cerydra, this gives her Military Merit before combat. This will transfer to whoever the active character becomes. At the start of the next battle, Cerydra will automatically use her Skill on the character with Military Merit without using any Skill Points, accelerating the first instance of Peerage within a fight, and immediately granting the benefits of Military Merit.

[Bonus Traces]

A2 is a stat conversion Trace. For every 100 ATK that exceeds 2000, Cerydra will gain 18% CRIT DMG, up to a maximum of 360%. This caps out at 4000 ATK, and you are already incentivised to build for ATK for the purposes of Military Merit's ATK buff.

A4 will increase Cerydra's CRIT Rate by 100%. While her Charge is below the maximum of 8, Cerydra will gain 1 point of Charge when the character with Military Merit uses their Ultimate. This, bizarrely, has a trigger limit of once per battle, rendering its usefulness extremely suspect.

Lastly, A6 will grant added functionality to the Skill. When Cerydra uses her Skill, she will grant an additional 20 flat SPD to herself and the teammate with Military Merit, lasting for 3 turns. Also, when characters with Military Merit use Basic ATK or Skill, Cerydra recovers 5 Energy.

Flat SPD is fairly rare to have and can make SPD tuning your powerful DPS characters much easier (but also much harder depending on the exact team). Extra Energy is always appreciated, especially since it can aid in the acquisition of more points of Charge.

[Eidolons]

The dreaded heading appears, and thus the cycle continues. Cerydra's E1 is particularly curious because of a small detail at the end.

The E1 makes the character with Military Merit ignore 16% DEF when dealing damage, active at all times. If this character has Peerage, this becomes 20% DEF ignore for specifically Skill DMG. So far, so good, right? A pretty strong and always useful boost. But there's this extra bit at the end: When Cerydra uses her Skill, regenerates 2 Energy for the designated ally target. 2 Energy is pretty much meaningless to everyone, especially for the many DPS characters we have now with very large Energy pools. Except for one... Phainon.

This is pretty much 'The Phainon Eidolon'. While the token amount of Energy restored matters not for anyone else, Phainon does not actually care about the specific amount restored, just that it indeed restores Energy.

This means that with E1, every Cerydra Skill will restore 2 Coreflames to Phainon, vastly accelerating his ascension into his Ultimate and greatly reducing the downtime between ascensions. This is a shamelessly targeted Eidolon, and is incredibly worthwhile to pick up if you are intent on playing a lore-accurate Phainon.

[The rest]

Cerydra's kit is pretty straightforward after you get through the myriad proper terms she has floating about. The game plan is simple: get to 6 points of Charge as quickly as possible so that the buffed DPS unit can double up on their Skill usage.

Now if we just narrow down the number of DPS characters who fit the bill for this game plan... It's a shockingly short list, at least at the time of writing.

It should be apparent (especially with that E1) that Cerydra was designed to be the ultimate support character for The Deliverer, Phainon. Getting to throw down TWO full powered Meteors back to back in a single action is hilariously busted, and with a truly small amount of setup, Phainon gets to take advantage of Peerage twice in a single Ultimate duration. Cerydra also lets Phainon have another way of SPD tuning to his mandatory Action Advancing supports, thanks to her flat SPD buff from her A6. This doesn't necessarily make it easier to do so, but the proper order of actions can result in a very speedy first Phainon Ultimate. This is a good highlight for an issue that Phainon runs into here, and may be true for any future characters like Phainon: Phainon has an extraordinarily strong Skill that may take full advantage of Cerydra's buffs, but he struggles to gain the points of Charge very quickly on his own.

This is of course alleviated by his natural pairing with the AA characters (Bronya, Sunday, RMC), but it often still requires Cerydra to use her Skill again, both for the Coreflame it'll grant Phainon as well as for the point of Charge she gains herself.

SP can become quite the issue if one is not careful, and especially in the event that you cannot clear the encounter within a single Ultimate, you'll need to consider how exactly you're going to build towards Phainon's second Ultimate.

Not insurmountable by any means, and let me be explicitly clear when I say: Cerydra is a definitive upgrade for Phainon teams. There is no argument to be had here, and if you get her E1, Phainon will most assuredly be watchin' it burn.

Another fantastic character is The Feeble Scholar. Anaxa can't seem to stop winning recently, and this doesn't seem to be changing. All of the benefits that apply to Phainon will also apply to Anaxa, due to Anaxa's damage profile being almost exclusively Skill DMG. He already doubles up on Skill uses thanks to his own Talent, so how exactly does this interact with Cerydra's Peerage buff?

Four Skills. Four Skills IN A ROW, in a single action.

The man literally gets his full Ultimate back in a single action, and both parts of his natural double-Skill benefit from the Peerage buffs. It doesn't last for all four Skills, sadly, but two out of the bunch get the full bonus. Even better is that Anaxa's Extra Skill use counts towards generating Charge for Cerydra, meaning he has a fantastic time of activating Peerage consistently and quickly (even more so if he's paired with an AA support). Yes, this even counts for using his Basic ATK, so if you want to really expedite the acquisition of Peerage, you can use Cerydra's Skill liberally even at low SP, since Anaxagoras will always have at least one Skill ready to go.

Funnily enough, if you reach 6 points of Charge with Anaxa's Basic ATK, he will immediately use Peerage's Coup de Main, launching two Skills after the Basic ATK, and then the third Skill that was initially meant to follow the Basic ATK. As such, it's really difficult to not make good use of Cerydra's bonuses.

These two DPS characters, Phainon and Anaxa, Student and Professor, are the most overt winners of Cerydra's design. They are already two of the heaviest hitters we've got, and have extremely scalable and adaptable kits that can take well to almost any support.

Cerydra is undoubtedly great for them, but she is not their only option, and outside of these two DPS, and especially for other DPS characters who are not predominantly Skill DMG based, Cerydra starts to compare most unfavourably to the current best support options.

[Wrap up]

Cerydra's got more than a few tricks up her sleeve to propel Skill based DMG dealers to new heights, but she's firmly placed within her niche. Her power starts to be diminished once you start directly comparing to existing Harmony (and in some cases Nihility) support options, as those are typically more generally applicable.

However, it is important to note how Cerydra herself plays with these other supports, and especially with the Action Advancing supports, Cerydra can become even more powerful in her niche. If you are in possession of at least one of Phainon or Anaxa, Cerydra is an excellent pickup for you. She boosts them by enough that it almost seems a little overkill to have Cerydra when these DPS characters are already at the top of their game.

But this may yet change, and enemy HP continues to grow rather rapidly. What may seem like overkill now may very rapidly become a sigh of relief, and sooner than you expect (or hope).

The ones from beyond the sky say 'make a choice you won't regret', and the Sovereign Cerydra agrees with them, for she is charting a journey across the stars, and wants only the most loyal to accompany her.