How to Complete Veis, Assassin

This is a speed battle vs. House Bowen, so one of your units has to deal the final blow to the Malboro. If a unit from House Bowen deals the final blow instead, you will fail the quest.

There is a treasure chest on the field that contains a Mimic enemy. Releasing this enemy might distract House Bowen, giving you a better chance of success. You can also physically block the path to the Malboro, but be sure to get rid of the Illusionist, who can damage the Malboro without being close to it.