Optional Boss: Assassin Girl

[Zeiros Lion]

Currently in Act IV and finally opened up NE Perpetua. At the end of the screen is an optional boss called Assassin Girl.

She does one of three actions per turn:

👉🏻 Insta-kills 2 random party members (ignores defense and buffs AFAIK);
👉🏻 OR, uses Thousand Daggers, which brings everyone's HP to 1, but does not kill (again, ignores defense and buffs);
👉🏻 OR spends the turn to dash back to the next phase of the fight

She is weak to 💧 Water, so I am trying to deal damage each turn while making sure I have more than 2 party members alive at any given time. I more or less got this part of the fight down.

On the third phase change, she summons a minion (no elemental weakness) who heals her for 500 HP each turn. Again sticking to the above strategy to make sure she at least doesn't gain net HP back, and because defense isn't an issue here.

But the FINAL phase is what is killing me.

In addition to the boss and the healer minion, she summons a second minion (again, no elemental weakness) who does physical AOE damage each turn. Suddenly, defense is important if you don't want a party wipe. And even then, it's an RNG fest because turn order and actions from the Assassin Girl can ruin everything.

Here's my setup so far.

Amalia 🔁 Anyone (Amalia ALWAYS needs to be up because of Raise All)
Sienna 🔁 Victor
Mikah 🔁 Ba'thraz
Lenne 🔁 Glenn

Phase 1-3:

1️⃣ Amalia (Rezzer with Shaman so she can use Aqua when she doesn't need to rez)
2️⃣ Sienna (Petal combos and emergency rezzes of the rezzer with items)
3️⃣ Mikah (Tiger combos with Water Attack for BIG DAMAGE)
4️⃣ Lenne (WATER THRUST BABY!)

Notes:

👉🏻 Best start I can get is with Mikah before the boss, so she can use Opener for an easy 1100+ damage.
👉🏻 I always raise Amalia first if she gets KO'd.
👉🏻 When Sienna runs out of TP for Petal combos, I put her on item duty to replenish TP as needed for everyone else, especially Mikah.
👉🏻 I try to complete Tiger combos with Mikah if you can for at least 1100-1200 per combo with my current setup.
👉🏻 If Lenne runs out of TP before the final phase, I can swap to Glenn if need be to continue with Water Strike.

Phase 4

1️⃣ Amalia (double duty for heals/rez)
2️⃣ Swap Sienna to Victor (Requiem defense buff and additional heals/rez)
3️⃣ Keep Mikah if possible, swap to Ba'thraz because his magic still does damage.
4️⃣ Swap Lenne to Glenn because he has more defense to deal with the AOE minion.

Notes:

👉🏻 I always get destroyed by RNG. Usually it's either: 1️⃣ Boss gets Thousand Needles out, immediately followed by the AOE minion; or 2️⃣ she insta-kills someone in the turn order between her and the AOE minion.

This is a devilish boss fight, and I feel like I'm missing something VERY important here. Either it's just a matter of damage output, or maybe that the first few phases don't count for damage. I don't know and it's driving me batty!

Any tips or tricks?

[slydogg9692]

Beat her woth Glenn, Amalia, Sienne, and Egyl with no switching.

The boss is basically one big DPS check: kill her as fast as possible. All phases, especially the early ones, are crucial. Don't even bother attacking her summons.

Glenn is there for All Break (preferably with a break extender crystal) to debuff the boss.

Amalia is there for rez and aoe healing once the 2nd summon comes. Equip the Silver Lining passive to save yourself one res.

Egyl will use Iron Will and Luring Bang to draw aggro from the boss. He can tank two of the boss' insta kill hits with Amalia's Revive as a back up.

Sienne can use Shadowstep to avoid the insta kill hits at lrast two times.

You can probably switch around Glenn and Sienne for other DPS but I think Amalia and Egyl are key. There may be more efficient methods (how about the entire team having Silver Lining?) but this is how I beat her.

For reference, I beat her right before I finished the final dungeon of the game.

[Zeiros Lion]

Those are some skills/crystals I don't have yet. I'll have to revisit this boss when I get them.

Thanks for the help! 🙏🏻

[Lightbearer]

@slydogg9692 is right that it's an end game DPS check. My set-up was completely different and focused on exploiting her water weakness with Victor's Ifrit song (reduces elemental weakness by 35%), Robb's attack that reduces elemental weakness (one of his final skills), Lenne's water coat on the weapons, and Sienne with ridiculously high AGI to maximize her Dragon attack that hits multiple times. Layer on top of that buffs from Victor and debuffs from Glenn. Amalia is used as a back-up revive panic button as needed. I did this fight just before the final boss fight. The item you get (elemental tablet) is for the "ultimate" boss in the game, so it's not like you're missing out on an important reward.

[Noules]

I was able to kill her before Reina's Grave.

Stacking agility on Sienna with Dragonfang basically wins the game. You can stack Quickstep, Mikah's Double Steps, Monk's Drunken Master, Victor's Heroic Ode with two copies of Agi Up (her own, and the one from Bandit) with Winged Cape to take an obscene number of turns, Keeping up Shadowstep keeps Sienna alive from the insta-death attack. Everything else is just a matter of applying debuffs to the boss and spamming buffs on Sienna (who will blow through them incredibly fast due to her turn rate). The last summon never actually took a turn before the boss died.

My Sienna also has the Vampire skills mastered for self-sustain. Everyone else eventually died, but Quickstep with Dragonfang pulled it through. Water Cloak + Dragonfang on the debuffed boss did a lot of damage before Lenne eventually dropped.

I actually went into this fight without optimizing for it at all. Had no idea what I was in for but still one-shot it. If I was redoing this I'd probably gem water attack on Sienna's weapon so Water Cloak wouldn't be necessary.