Koka is one of the first stops for Guts on his path of revenge and ultimately the only location featured for the Black Swordsman Arc in the anime. Also, Koka is the first setting in the manga and first anime series.
The town is depicted being situated within a plain, with rolling hills and riverbeds surrounding the exterior. Further out can be spotted mountaintops and forests at their base. The town itself is built much like any other, many small to medium size buildings incased within a walled fortress of sorts with a dark, overlooking castle atop the highest hill within its foundation. For the most part the town is rather clean, little to no homeless or diseased roam the streets and it either contains its own brothel for men to enjoy a drink every now and then. Apart from the castle, there is a dungeon situated somewhere across the city that contains torture devices and a wretched holding cell lined with haystacks and leftover waste from previous captives. This is most likely where the vagrants, women and children are kept before being shipped to the Baron.
Guts first enters this town, in search of the local Apostle lord. After passing a caravan containing women and children prisoners, he makes his way into the local tavern. Here he meets up with Snake Baron's Bandits tormenting the elf known as Puck by tossing daggers at him. Guts, probably annoyed by their behavior, kills all but the leader whom he leaves alive for the purpose of relaying a message to the Snake Baron that the Black Swordsman has arrived. Some damage is caused to the tavern in this struggle but ultimately it most likely burns down in the coming raid by the Baron.
Guts makes his way through the streets with the elf Puck tagging along until he is caught by the local guardsman that are under the employ of the Lord Mayor of Koka. They proceed to take him to the local dungeon where he is tortured until questioned by the Mayor, whom upon being found out by his deeds condemns Guts to further torture as long as the torturer desired. Meanwhile, the Mayor pays a visit to the Snake Baron that turns into a deadly meeting where the Mayor is whisked off and presumebly killed. As Guts lays in his cell after enduring the pain of constant lashes, Puck shows up to help Guts out and after his freedom, he noticed outside that the town is on fire.
The Baron and his men are raiding the place, killing everyone in their path and burning every building as he watches them suffer in a fiery inferno. Guts reclaims his weapons and starts an attack, slaying many of the henchmen under the Baron's employ and ultimately duels with the Apostle himself. After a close match, Guts comes out victorious and watches as a collapsing building (that was already in flames) falls on the Apostle and ultimately scorches him alive. As Guts walks off, there can be many bodies seen around him and Puck gives chase after this. Nothing is heard of Koka from this point on, so either the entire population was massacred or only a few survived and moved to a different town since this one was in ruin.
- While the town exists evenly in both the anime and manga, there are various differences that mainly have to do with the inhabitants. Colorschemes, titles change and even some deaths are in different order.
- Puck does not exist in the first anime series, as it is meant to cover the entire Golden Age Arc and Puck's involvement is not necessary for it.
- The events proceeding this would have led Guts and Puck into a deep forest filled with the undead (as in the manga) for the first anime, but instead the following episode starts right out after Guts' childhood when he faces down Bazuso.