Armoured demon, Uncommon 4g4r
Demonic. Durable.
Attack: 6
if wall is divisible by 5
enemy wall: -5
if tower is divible by 5
attack: 5
I like this. Particularly since the Demonic keyword means that you're taking either wall or tower damage between plays. If your wall is reduced to 0, your opponent's wall is next to fall. Seems balanced well for a Durable.