In Berserk, the Berserker Armor is a cursed suit of armor that grants its user incredible strength and endurance by allowing its wearer to bypass the normal subconscious limits that prevent him from injuring himself when using his full strength. It can temporarily fix injuries by binding bleeding wounds, reinforcing broken bones and fixing dislocated joints. It can also send its user into a berserker rage where he cannot tell friend from foe. Long-term use of the armor can cause chronic mental deterioration, as well as severe physical effects.
When in Berserker mode, the armor takes on the appearance of the user's inner "beast." For Guts, the current wearer and user of the armor, this is the Beast of Darkness, the demonic hellhound-like wolf that represents all the hatred and evil that dwells within his soul, which becomes stronger every time Guts uses the armor.
