The Skull Knight is an enigmatic character in Berserk who wears full armor with skull-shaped ornaments on his helmet. He's a formidable warrior and rides a massive black horse. Despite his ominous appearance, he opposes the Godhand and its followers. His main goal is to hunt down Apostles and consume their Behelits, especially targeting Zodd the Immortal in a bitter rivalry. The Skull Knight wields a powerful sword that can turn into a Behelit-coated blade when stuck through his throat, allowing him to traverse dimensions with ease.
He was the wearer of the Berserkers Armor, and knew the witch Flora. During the duel between Griffith and Ganishka he suddenly appeared out of thin air through a dimensional rift, trying to land a fatal blow on the Hawk, only to see it diverted on the writhing body of the Kushan Emperor.
This enigmatic knight saved Guts in more than one occasion, notably during the infamous Eclipse which saw Griffith become a member of the Hand of God or when Slan almost slaughtered him, though he never explained why, simply declaring that the Struggler (the way he calls Guts) has to keep following his fate.
During his life as a mortal, the Skull Knight was in fact Gaiseric, the warlord that unified the Midland and became its first Emperor, notorious for his helmet whose shape was that of a human skull and whose ambitions prompted God to send four Angels (most likely the four members of the Hand of God) to punish him.