Honkai: Star RailAcheronBest build, teams and other guides

Acheron is an extraordinarily powerful DPS character. Similar to Feixiao, she has a unique Ultimate which works on a stack-based system instead of the usual Energy mechanic. Stacks are gained whenever Acheron uses her Skill or when allies apply debuffs on enemies. Acheron also boasts some of the absolute highest self-buffing capabilities, with the only requirement being to have two other Nihility units alongside her. She also reduces enemies’ All-Type RES during her Ultimate and even reduces their Toughness regardless of type. All of this together makes Acheron an absurdly potent and near-universally applicable DPS.

Definitely not Raiden Mei made quite the entrance in the early story of Penacony, and now we finally get a glimpse at what she’s capable of. Spoiler: It’s a lot. Let there be no doubt in anyone’s mind that Acheron is inarguably vying for the top DPS spot.

I will actually lead off by saying that Acheron is a very challenging unit to play properly. It takes a lot of attention to detail to make the most out of her kit, and even though her damage ceiling is among the highest in the game, it does not necessarily come easily. If you do not take the time to learn her kit and how it works, you should not expect her to perform to her best. She’s very worth the effort, but it has to be said either way. You have been warned.

Her Ultimate is the most intriguing part of her kit, but we actually need to talk about her Talent first so that it makes sense. Yeah I know, but this is the way it is sometimes. The first part of Acheron’s Talent states that her Ultimate can be used upon reaching 9 points of Slashed Dream, and the Talent additionally reduces all enemies All-Type RES by up to 20% during Acheron’s Ultimate. 1 point of Slashed Dream can be obtained by Acheron herself through her Skill and through allies applying debuffs on enemies.

The next part of her Talent involves stacking Crimson Knot on enemies. Whenever allies apply debuffs on enemies, in addition to incrementing Slashed Dream, they will also inflict 1 stack of Crimson Knot. If multiple enemies are debuffed, only 1 point of Slashed Dream will be gained by Acheron, and the enemy with the highest number of Crimson Knot stacks will get an additional one. Whenever an enemy target leaves the field or is defeated while Acheron is alive, their Crimson Knot stacks will be transferred to the enemy with the highest number of Crimson Knot stacks.

Crimson Knot is important for Acheron’s Ultimate. Upon using Acheron’s Ultimate, she will draw her blade and enter a targeting mode similar to what Destruction Trailblazer does in their Ultimate. She can unleash 3 giant slashes, being able to switch targets in between attacks, followed by an automatic finisher slash at the end called Stygian Resurge. Each of her 3 targeted Rainblades will remove up to 3 Crimson Knot stacks from the targeted enemy, increasing the damage the slash deals based on the stacks removed. 

This totals out to be up to 372% ATK to a single enemy, and 300% ATK to all other enemies. This is an extreme amount of AoE damage all on its own, and it’s not even the final form of the Ultimate yet. The finisher slash will remove all Crimson Knots and Crimson Knot cannot be reapplied during the Ultimate.

The majority of the damage from the Ultimate actually stems from the AoE portion. The way it works is that the AoE portion deals damage based on how many stacks of Crimson Knot are removed by the targeted slashes. You have the ability to change your target during this Ultimate, so it is imperative that you target enemies with at least 3 Crimson Knot stacks on them for each and every slash or you will not get the full amount of listed damage. The Ultimate will straight up show you above the enemies’ heads how many Crimson Knot stacks they have, but if you are really unsure, then genuinely you can just put her on Auto for the duration of the Ultimate and it will handle it for you. Her Auto AI is surprisingly good.

Acheron’s Skill will give her 1 point of Slashed Dream on use and deals damage in a Blast AoE, up to 160% ATK to the main foe and 60% ATK to adjacent targets. This assists her in getting her points of Slashed Dream but is too slow to rely on getting her Ultimate quickly without having debuffing teammates.

Interestingly enough, her Technique is actually worth talking about. She attacks the enemy and instantly defeats them if they’re a normal enemy. Yes, this works in the Simulated Universe too. If they’re worthy enough to survive the immediate death, Acheron will deal 200% ATK to all enemies on the field, depleting Toughness regardless of Weakness Types, and will gain 1 stack of Quadrivalent Ascendance. This status will immediately refund 1 point of Slashed Dream after Acheron’s Ultimate ends and stacks 1 Crimson Knot on a single random enemy, serving as a head start towards her next Ultimate. This triggers on every subsequent wave as well, meaning she gets free points and stacks every time more enemies come up.

This AoE damage and free stacking will actually occur on every subsequent enemy wave too, meaning Acheron always has a leg up on her foes. You can also just spam it freely to look cool because it only consumes the Technique Point if you actually hit an enemy.

Already it looks very impressive, but you may be wondering how likely you are to be doing good damage if you need to rely on having debuffing teammates instead of the usual Harmony characters like Ruan Mei, Tingyun, or Sparkle. This is where Acheron’s Bonus Traces come in to elevate Acheron to a new and ridiculous height.

Acheron’s A2 makes it so that when entering battle, Acheron will immediately start with 5 points of Slashed Dream and will apply 5 stacks of Crimson Knot to a random enemy. This greatly speeds up the process of getting her first Ultimate. In addition to this, when Slashed Dream reaches its cap of 9, excess points of Slashed Dream will be stored in stacks of Quadrivalent Ascendance, up to a new max of 3 stacks. When Acheron’s Ultimate ends, these stacks of Quadrivalent Ascendance are consumed to restore the equivalent number of Slashed Dream points. This essentially means that you can overcap on Slashed Dream by 3 points and not lose out on potential damage.

Her A4 provides a bonus to damage dealt when there are other Nihility characters in the team. If there is 1 other Nihility character, Acheron’s Basic, Skill, and Ultimate will deal 115% of the original damage, increased to 160% of the original damage if you have 2 other Nihility characters. 

I want to make this explicitly clear; this is an entirely separate damage multiplier. This is a damage boost that operates outside the confines of the DMG formula, meaning it is not beholden to diminishing returns, operates as stated, and is applied after everything else has been considered. This is also the first of its kind, and is an absurd self-buff that rivals and even slightly exceeds what many of the strong Harmony units we have can provide.

This is also for any Nihility units by the way — you don’t have to stick to just the classic Pela and Silver Wolf, you can be free to do whatever ridiculous combination you want and it’ll still work extremely well. This also means that as long as the characters you’re considering for her team are Nihility, her teams are among the most flexible in the entire game, letting her essentially act as a pseudo-universal DPS due to her absurd damage numbers, RES ignore, and Toughness ignoring damage. 

This remains true in the reverse situation as well; adding Acheron into an already existing Nihility team is completely effortless and requires literally no extra steps. You want to do a simple Acheron-centric team with someone like Pela and Welt? Easy-peasy. Perhaps you want to watch the fireworks with Guinaifen and Sampo? No problem at all. Or maybe you’re just cultured and like tall women, and so want to put Acheron with Kafka and Black Swan, and if so, you’re in luck, because It just works™. 

The other outstanding benefit of this Bonus Trace is that it means Acheron quite simply doesn’t need or even necessarily want what the Harmony characters provide, meaning they are entirely free to be used by your second team. With Acheron in the mix, no longer will you have to carefully weigh up which team you’re going to have to make weaker by not giving Ruan Mei or Bronya, which team won’t have the endless SP of Sparkle, or the Energy gains of Tingyun. This will no longer be a consideration you need to make because it’s all quite simple: you just put them on the team that Acheron isn’t on.

By restricting the activation of this Talent to only other Nihility units, Acheron frees up the best supports in the game to be used by other characters who need it far more than her, ironically becoming a far less restrictive unit than one might incorrectly assume. Even then, when your restriction is the entirety of a Path that is also notorious for doing whatever it damn well pleases… Well I just wouldn’t even call that a restriction to be honest.

Finally, Acheron’s A6 just adds to this ridiculousness. When the Rainblade from Acheron’s Ultimate hits enemy targets with Crimson Knot, her DMG increases by 30%, stacking up to 3 times and lasting for 3 turns. When Stygian Resurge ends the Ultimate, she will deal 6 additional instances of 25% ATK damage to a random enemy, and this damage is considered Ultimate damage.

This means that over the course of her already brutal Ultimate, Acheron also gains a 90% DMG bonus as well as increasing the final multiplier by 150% ATK. Remember, of course, that all of this is in addition to the Talent’s bonuses of reducing the All-Type RES of enemies by a whole 20% and having all the damage ignore Weakness Types too. Oh, and since the DMG bonus lasts for 3 turns, it’s actually quite possible to have this be up almost indefinitely if the rest of the team can apply debuffs quickly enough for Acheron to regain points of Slashed Dream.

This makes her Ultimate deal pretty impressive damage, comparable to the likes of an Imbibitor Lunae Fulgurant Leap or a fully stacked Lightning-Lord. As soon as there’s 4-5 enemies showing up on the field, this Ultimate starts to run away with it and it becomes quite simply the single most devastating move in the entire game, and it’s not even close. It’s not even remotely close. 

I hesitate to even mention her Eidolons because quite frankly I think it’s all whale-bait. Acheron is already basically the best DPS in the game at E0 — yes it does require some non-free units to really use since Hoyoverse have yet to make any 4-star Nihility units free, but still, it’s a comparatively small price to pay compared to some other top dogs.

Hear me now, anyone who says that Acheron needs Eidolons is both hilariously incorrect and afflicted with downright crippling Skill Issue. None of this is likely to ever be necessary because it’s just a level of power that you’ll literally never get to use. If you are just shilling for your queen, however, I have good news, since all of her Eidolons are pretty good past E1; her first Eidolon is a bit lacklustre given the insanity of her base kit, so it’s mostly a stepping stone for later Eidolons.

Acheron sees a remarkably high benefit from getting her Signature Light Cone. You should know that if a Light Cone passive inflicts a debuff, it’ll also grant Acheron 1 point of Slashed Dream, which means she’s more drawn to Cones that can do that. Coupled with the insane amount of damage she gets from her Signature, it makes going for Acheron’s Light Cone quite a compelling choice, especially since it also applies a debuff. Currently, this lack of Light Cone options is a really big weakness that Acheron has.

That said, she doesn’t need her Signature Light Cone to perform extremely well. Acheron has some good 4-star options for Light Cones but they are unfortunately locked behind gacha, and the free Nihility Light Cones are more tailored towards the Damage over Time centric characters like Kafka. Do not fret too much, as even the super free-to-play options are still more than enough for Acheron to decimate everything, but you still want to keep an eye out for a copy of Boundless Choreo or Good Night and Sleep Well, as well as keeping an eye out for any potential future Nihility Light Cones.

Teammate-wise, a Preservation unit holding Trend of the Universal Market is technically the best option for maximum debuff spreading for the sustain choice, but it can be a tad unreliable on anyone that isn’t the Preservation Trailblazer, since they can Taunt enemies into attacking them. It’s a very meaningful optimisation, but is not worth running if it costs you overall survivability (such as if you don’t have any other Preservation units and have been neglecting your Preservation Trailblazer). Gallagher, who was released in this same patch and is an Abundance unit with debuffing capabilities, so he is going to be the next best choice in this regard if you do not own a copy of Trend of the Universal Market.

Interesting to note as well, if you are lacking a compelling second other Nihility unit to use with her, but you have Sparkle, you can use her and get pretty decent results, but do note that if you choose to do this, your Sparkle has to be extremely well built to make up for the severe damage loss you incur by not fully activating Acheron’s A4. If your Acheron is E2, Sparkle becomes her best teammate technically, but the damage is such overkill that bosses would need their health tripled or something ridiculous like that. It’s not unconditionally better than just using the second Nihility character, so don’t try and brute force it if you have options, because Sparkle is far better spent on other DPS characters who actually need her.

Because of Acheron’s universal strengths and versatile team comps, she’s actually a character you may consider going for even if you already have other well-built DPS units. Acheron does what she does in a unique and powerful way, and she frees up all of your strong Harmony characters to be used on your second team. She definitely isn’t as plug-and-play as some people would have you believe, you still need to actually invest in her and her teammates, and this can be tricky since another big draw of her Nihility teammates is that they’ll be contributing their own damage to the team. They can’t do that if they’re not geared.

The other thing to consider before pulling is ‘do I actually even have enough good Nihility units to pair with Acheron?’, because if the answer to that question is no, then you may need to think a little more about this, especially when also factoring in the aforementioned Light Cone woes you may encounter. Pela and Resolution Shines as Pearls of Sweat are pretty much the minimum you’d need for it to be a real recommendation, but if you’re expecting to get those soon, or if you simply don’t mind all that much, then make your own decision. For the premium options for the Nihility spot, you have Jiaoqiu who is Acheron's best partner. He provides her with everything she needs and elevates her performance to new heights.

You have to remember that this is Acheron in her absolute base version without any specialised teammates, but they further amplify her potential. It can, quite literally, only go up from here, and that’s somewhat terrifying actually. I mean think about it like this: any future Nihility unit has the potential to be paired with Acheron, and anything they provide is going to be passing through that final 1.6x multiplier from Acheron’s A4. 

Acheron is a teammate for life, and someone you can count on to be a top contender for a very long time, and if future Nihility units are tailored to her game plan, maybe even longer than that. The last thing I’ll say is to be prepared to grind for her best equipment, because it all adds up a lot. If you settle for ‘good enough’, don’t be surprised when she doesn’t live up to what she’s capable of.

If you can meet those requirements, you’ll have bonafide Lightning on your hands. Do you know why they say Lightning rarely strikes twice?

… It’s because she usually doesn’t have to.