Lava Fish

A boss with a Burn stacking gimmick. Take too long and it'll Burn your party to a crisp, but it's potentially the easiest of the bosses.

The general strategy is to have a tank, a healer and some units that can attack from a distance, simply keeping your tank alive and keeping out of newly formed lava tiles. Noted that taking too long will result in your healer not being able to keep up with the Burn stacks.

However there's any number of negating Burns or even using it to your advantage. There are a number of skills that can remove Burns such as Cleanse. Water creation skills also trivializes the Burn damage. The Heat Resistant trait will negate Burn damage altogether, though even better is combining that with Burning which will add those Burn to your damage.

Upon defeating the Lava Fish you can choose to harvest it for a consumable LavaHeart, two LavaScaleArmor which are some of the best armors in the game, giving an overall stat boost with no downsides, as well as material LavaScales that can be used to craft more. Alternatively you can choose to watch and raise the max morale of your party.

It should be noted that any boss fusion or offspring lose the Giant trait, so if you wish to obtain a boss in all its glory you need to capture them.