Are you trying to force-move the unit that kills the boss, or let the player move them after killing? If it’s the former, being greyed out doesn’t matter; you can still move them around with events. If the latter, you can unset the has_moved bit using UNCR char_id 0x2 (FE7) or SETVAL 0x1 0x2; UNSET_CONDITION char_id after installing this hack.