How to Complete Bringer of Doom

The objective is to defeat The Smoldering Incubus. Reaction Abilities are forbidden.

You might want to equip the Chirijiraden sword on Adelle before you begin the battle, and switch Adelle to the Heritor job if she is currently something else. This will give her the Hilo ability, which is a ranged attack.

Put other units into the battle that can do ranged attacks, since it is not possible to go directly to the mark. The enemy can inflict Doom and Charm, so equip protection against those effects if you can.