Koi`Doken has a ridge you can stand behind. The locations you can stand vary. You can be up closer to the ledge where it is shorter, and farther away from it where it is taller. Standing in the right spot allows you to hit with archery while avoiding the AoE. You’ll probably take an AE or two trying to find it. The image below shows an area farther from a taller region that was safe, as well as a shorter region that was safe on the right. You’ll find your spot.
Zeal map location:
