Honkai: Star RailAstaBest build, teams and other guides

Asta is a universally applicable support specialising in increasing the whole team’s ATK and providing a massive teamwide SPD boost. Her Ultimate increases SPD by a flat 50. Asta also benefits from a fairly strong Skill that Bounces damage between enemies, allowing her to stack up her ATK bonus easily and deal tremendous Toughness damage for a support.

The Lead Researcher of the Herta Space Station has steadily become more and more recognised by the playerbase. Her kit is always appreciated and always powerful, and it’s become very clear that she is one of the most versatile and useful 4* support units, especially for new players that lack limited Harmony units.

Asta’s Talent has you gain up to 5 stacks of Charging. You gain a stack for every hit against a different enemy, and you get 2 stacks if an enemy you hit is weak to Fire. Each stack of Charging increases the entire team’s ATK by up to 14%, meaning the maximum total ATK boost is 70%. After her second turn in a fight, she’ll lose 3 stacks of Charging at the start of every turn. 

This is a very powerful boost that is quite easy to maintain at higher stacks. Even if there is only a single enemy on the field, you will always get to have at least a permanent 14% ATK boost since Asta’s turns are spent either Basic Attacking or using her Skill, increasing to 28% permanently if the enemy is weak to Fire. This is also the amount you can expect if Asta is played exclusively SP positive. As soon as more enemies start showing up, Asta can start very easily racking up stacks of Charging each turn with her Skill.

Her Skill is a Bounce attack; a multi hit attack where you land the first hit against your primary target and the remaining hits can randomly land on any target, including the original one. This deals up to 50% ATK to the first enemy and Bounces 4 times, each Bounce hit also dealing 50% ATK. Bounce attacks will also deal Toughness damage on each hit, with the hits beyond the first dealing a reduced amount. This Skill will end up dealing a total of 90 Toughness damage across its 5 hits, the same as most single-target Ultimates but on a Skill.

With Asta’s Skill it becomes possible to gain many Charging stacks easily, though with a slight amount of randomness involved. If you’re against a full house of 5 enemies and are lucky, you can get 5 stacks of Charging by getting a hit off on each of them, even if none of them have a Fire Weakness. If any of them do have a Fire Weakness, it becomes a lot more consistent to gain 5 stacks, though as mentioned before, even a couple of stacks can already be significant. 

This Skill even has a pretty impressive total multiplier of 250% ATK, particularly impressive against a single enemy. While Asta is not likely to be built specifically to deal damage, any damage stats that you do end up getting can actually end up being quite impactful in combat.

Asta’s Ultimate is extraordinarily potent, increasing the SPD of all allies by up to a flat 50 for 2 turns. Anyone who’s familiar with turn-based games understands that any amount of additional Speed can be devastatingly powerful, and this is no exception. An additional flat 50 SPD is a huge increase for every character, and all of them except for maybe Clara greatly appreciate this. 

For many characters, SPD is of paramount importance as it streamlines gameplay and rotations, increasing overall ease of performance. At lower SPD values, some characters can range from ‘uncomfortable’ to ‘virtually unusable’, and getting more SPD is a tough ask as it’s one of the rarest substats in the game. Asta can completely alleviate this issue and then some.

However, this does not mean that the value brought by Asta’s Ultimate is in any way diminished by characters who already meet their necessary SPD thresholds. As this boost is teamwide, everyone benefits from this, including Asta herself. Against many high-level enemies, without a sufficient amount of SPD you’ll be getting lapped several times over and might end up falling as a result — your support characters also need to be fast to keep up with your fast damage dealers and especially against the ever-accelerating enemies. 

At the higher end, for characters that are already exceeding their designated SPD values by a lot and reaching above 150, it is possible to exceed the 200 mark with Asta, thus transcending into double-turn territory, something that is practically impossible to attain without Asta, as most character’s Base SPD values are just too low.

It is important to understand that you can end up fumbling Asta’s Ultimate somewhat; it’s not correct to call it ‘misusing’ but there is a rather steep prerequisite to understanding how to use this Ultimate optimally, and that’s actually knowing how SPD works. Many have tried to explain this before, and it’s a concept that can get very messy and complicated.

Instead, here’s the cheat sheet for using Asta’s Ultimate: go to your settings and enable ‘Display Action Values’ and you’ll see some numbers in the turn order that’ll essentially show how far away the next turn is. When the number is bigger, use the Ultimate, it’ll end up pushing your characters’ turns up more. There is also a peculiar interaction where if you use this Ultimate on a character’s turn before they act, they’ll end up getting an ‘extra turn of the SPD boost’ — it’s not actually an extra turn of it, it’s more of a safety measure to prevent you from completely wasting a turn of the SPD boost.

Aside from that one peculiarity, there’s really no wrong way of using Asta. None of her supportive benefits scale off of anything besides Trace level, meaning it’s up to the player how they want to build her; going for a more offensive playstyle with CRIT, or going full tank with 6000+ HP, it doesn’t matter one bit as long as she’s staying alive long enough to get her support out.

Asta’s Bonus Ability Traces can be quite useful. Her A2 gives her Basic ATK an 80% base chance to Burn enemies for 3 turns, making them take 50% of Asta’s Basic ATK in damage. This deals quite literally no meaningful damage, but it is a source of a debuff which can be potentially useful for certain character synergies like Guinaifen’s Firekiss. A4 will increase all allies’ Fire DMG by 18% while Asta is alive, which is a free and appreciated boost to Fire centric teams or damage dealers. A6 is probably the most generally useful one of the bunch as it increases Asta’s DEF by 6% per stack of Charging, potentially giving a 30% DEF boost for free, aiding in her survivability further.

Asta is already superb at E0, and while she doesn’t necessarily get a huge performance boost from Eidolons, she does get some pretty significant improvements to her overall usability. E1 will add an extra Bounce to her Skill, increasing the damage to 300% ATK, the Toughness damage to 105, and offering an extra chance to get more Charging stacks. E2 is a very big milestone as it will delay the decay of Charging stacks for 1 turn after using her Ultimate, letting her maintain higher stacks of Charging for longer without spending as much SP, and also allowing to nicely line up all of her benefits for big bursts from your damage dealers.

E4 will increase Asta’s Energy Regeneration Rate by 15% when she has 2 or more Charging stacks. This is easily her most impactful Eidolon, as this can allow for permanent Ultimate uptime with certain builds. E3 and E5 are very impactful for Asta as a support character, increasing her Charging stacks ATK boost to 15.4% per stack, and improving her Ultimate’s SPD boost to a flat 53 instead of 50. Even 3 extra SPD can be pretty significant so these ability level Eidolons should not be underestimated. E6 is the final comfort Eidolon, reducing the Charging decay to only 2 at the end of her turn instead of 3.

While in the 1.x era of the game, Asta was commonly used in many teams, with the release of Ruan Mei her usage rate dropped by quite a lot and nowadays she's being used as a substitute for those who don't have Ruan Mei (yet). If you're a new player, Asta will work well for you, but once you obtain some stronger limited Harmony units, you will most likely bench her.