Sorry he's giving you a tough time! The ??? enemies are all illusions, and will only die when the Manos bat dies. You have to just keep hitting the bat with everything you've got. He's weak to fire, and Merel can do a lot of damage to him with it especially if she uses Concentrate. You can also use Karuna's Lockdown impulse on ??? A to keep it from draining HP for a little bit. Hope that helps :D