How to activate berserk mode?

Hello?, please, answer my questions:

1) How to activate berserk mode , while in berserk's armor? And how does it work?

2) Can I get the same troops, which Hawk's army have, like giants, irvin's archers? They are seems impossible to defeat, eeven with 100 battleknights...

you press V to activate berserk mode. you can also use cheat to defeat them like ctrl+h to full up your health bar.