The Berserk is an Off-Hand Device for Assault agents. Activating Berserk improves the Assault's melee abilities for a short duration, boosting Melee damage and Protection as well as Ground Speed, helping them stay in range of their target.
Proper use of the Berserk device can help turn the tables in a variety of situations, particularily in PvP missions - blocking an opposing melee Recon, then activating Berserk while wielding the Impact Hammer can quickly teach them to find a better target. Likewise, often times Assaults from both teams will converge upon a Control Point, activate Range Shield, and proceed to beat each other with melee weapons - activating Berserk instead of the shield could be a key advantage.
The Berserk device is part of the 'Overdrive' group - an Assault cannot activate an Overdrive device while another Overdrive is still active.
A specific epic variant of Berserk is available for purchase at level 36 from Dome City's Assault Gear vendor for 50 Conquest Tokens. Uncommon, rare, and other epic variants are occasionally awarded upon successful completion of PvE and PvP missions.