Grandline Shinsekai: Episode 6

The Killing Joke is the sixth episode of Grandline Shinsekai.

Plot
Even with a ship and a crew, Entei is unable to find his way around the water of the South Blue. He, Lupe and Wonder end up washed ashore a mysterious island after a ferocious storm. There they end up in the middle of a bounty hunting war. For about a week bounty hunters have been journeying to the island in search of a mermaid with a large bounty on her head.

These bounty hunters have been getting picked off and killed by a man only known as the Joker. After encountering the joker themselves, Entei and his allies are unable to scratch him, but manage to fend him off before running into a mysterious blue haired girl. Before long, the Joker returns and claims this is the girl with the bounty on her head. Entei and the others prepare to fight him again in order to protect her.