The Baron of Koka Castle is an Apostle of the God Hand and the first antagonist of the series Berserk. He has made himself the local ruler of the town of Koka, in place of the Lord Mayor of Koka and feeds on the local prisoners.
The Baron is first shown sitting at his table eating a meal (which is later revealed to be human flesh) when he receives news from the leader of the bandits from the tavern that there is a man known as the Black Swordsman roaming about, looking for him. He then proceeds to ask himself in his mind if it could be him...when suddenly one of his men arrives to tell him that the Mayor has arrived, asking for forgiveness on the events that happened earlier that night. The Mayor expresses his deepest apologies as the Baron sits across from him at a table, interrupting him to state that he cares for his own life like the selfish, cowardly human he is. He then stands up and walks to his Armour, revealing his intention of burning the town in somewhat of a poetic manner and in his mind, he'll draw out the Black Swordsman. He orders the Mayor away, most likely to be executed or possibly eaten.
As Guts frees himself with the help of Puck, he watches through the bars to notice that the entire town is on fire. Many of the Baron's henchmen are shown slaying the town's individuals as he arrives on horseback, in complete battle Armour with a young boy (half of his upper body remaining) is turned into a fountain for him to feast upon his blood. Guts shortly arrives thereafter to challenge the Baron, eliminating all henchmen in his way to take on the Baron himself. Confident, he accepts the challenge and rides forward with his halberd to attack Guts...only to find himself quickly off his horse with multiple bolts from the repeating crossbow in his body and head. He stands up, practically unaffected by the wounds and is sent flying back with further bolts into a building behind him. As Guts approaches to finish the job, the Baron suddenly transforms into his Apostle form and uses his long tail to throw Guts back while causing him a bit of damage.
Now in his monstrous form, he arises from the darkness claiming that he'll eat Guts alive and goes on the offensive using his tail as a major weapon. After Guts is beaten to a pulp with blood gushing out of his mouth and laying almost motionless on the ground, the Baron approaches him and picks him up by his right arm to further degrade him as a human with more speeches. Guts however, pulls a trick on him by releasing his hidden arm canon directly into the Baron's face which blows off half of his head and allows Guts to land on his feet again. He then runs forward with the Dragon Slayer and cuts him down, spilling his innards across the floor and ultimately forces him to the ground unable to protect himself. Guts smirks, shooting bolt after bolt into his body to show him that despite the fact that they're incapable of killing him, they still cause pain and makes him savor it as much as he can. The Baron begs more and more for his life, but is unrewarded as Guts cares more for finding out about the God Hand...only to be disappointed when he's awarded nothing more than garbage. He then turns away, informing the Baron that he'll now perish in the ashes...and almost as if done in by Karma, the very town he set ablaze crashes down in the form of burning debris to crush and ultimately scorch him alive until he dies a painful death.