From their announcement:
Harrummph! The Kobold Ironscale is not at all pleased that he was relegated to the 7th day of Super Dungeon Explore. Best not to make him cranky.
The largest and strongest of their kin, Ironscales wear heavy iron armor that can turn blade and arrow alike. They carry tall shields and fight from behind them like mobile walls, this Shieldwall even provides some protection to the smaller kobolds that fight at their backs. Defense is not all an Ironscale is capable of. Their high ATT value combined with the Mob ability and multiple action points have led to them being the final foe many Heroes will ever face.