Ironclad thrives off of ways to draw more cards and play more cards every turn. Drawing upgraded Attacks can overpower the enemies quite quickly, while you block with your health pool and some defensive relics or powers. Aggression fits into this quite nicely. In longer fights it'll keep you drawing Attacks you need to kill enemies. Keep in mind that Ironclad also has Exhaust, so you can try to remove worse Attacks to keep drawing the best ones instead.
