Berserk - Berserker Armor -

The armor's appearance shifts to reflect the wearer's "inner beast." For Guts, the helmet takes the form of the Beast of Darkness , a manifestation of his trauma and bloodlust. The Terrible Price

The armor does not technically grant new powers; instead, it removes the user's subconscious physical limiters.

Instead of healing, the armor brutally "fixes" injuries by injecting thin metal spikes into the wearer's flesh to pin broken bones and joints back together, allowing them to continue fighting until their body completely fails.