How to defeat Trousseau in Octopath Traveler 2

Only want to see you laughing in the purple rain

The conclusion of Castti’s arc sees her memories come flooding back, and with them, a recollection of what she needs to do: Set out for Timberrain, and bring an end to her former compatriot’s wicked ways.

Spoilers follow for Castti’s Chapter 4 in Octopath Traveler 2.

With Trousseau determined to let loose more poisonous purple rain on the populace, Castti will have to take care of the lost apothecary herself. After climbing the castle’s ramparts and finding Trousseau, you’ll take on the one boss fight of this chapter. Even if it’s not a boss gauntlet, though, Trousseau’s got some challenges up his sleeve.

How to deal with Trousseau’s purple rain

The moody apothecary will turn this boss battle into a Prince song from the outset, bringing the poisonous rain down upon the battlefield. This is different from standard poison, as the rain will have its own separate turn; and rather than doing damage, it will reduce your maximum HP pool.

There’s no way of counteracting this effect, so this becomes a race against the clock. The longer the fight goes on, the more difficult it will be to survive Trousseau’s onslaught.

Best strategies for defeating Trousseau in Octopath Traveler 2

A key moment to note is that, after doing enough damage, Trousseau will shift phases. This is marked by him removing the mask, after a short exchange with Castti. Most final bosses of each path have these sorts of phases.

It’s important to hit this phase fast, but also be ready to lay on the damage once you do so. Trousseau will significantly up his attack output here. Luckily, you get some help. While his Phase 1 weaknesses are Polearms, Axes, Ice, and Darkness, more weaknesses will be added on in the second phase, including Swords, Staffs, and Lightning.

Essentially, he’s easier to break once in his second phase. Use that to your advantage, while also employing Castti’s Latent Power to keep everyone topped off. Rehabilitate is quite useful here for dealing with any lingering status effects, while some good concoctions can both heal and keep SP / BP resources high for big breaks. Remember, the longer this fight goes on, the worse it gets for you. Having heavy hitters like Hikari with Tenretsuzan, Throne with Aeber’s Reckoning, Osvald’s One True Magic, and Ochette’s Beasts and Latent Power attacks will help end this fight before it gets out of hand.