could you may look into this and work on this debuff the skills caused grenade and death bound give the enemy. They go to base stats and reduce max hp/hp and ATK/MATK, http://ds.irowiki.or.../Status_Effects.
It would be great if this rare debuff could be of use, i guess this could at least help the Overlord class already to grow in strength, since the debuff of the specialist is not compareable to the overlord ones.(overlord ones much stronger)