Similar to Black Battler, Dark Keiichi was created as a personification of evil Keiichi. Dark Keiichi first appeared as Umineko: Golden Fantasia DLC, but he later appeared in other works as an antagonist.
Despite his typical evil appearance, Dark Keiichi is actually a fun guy to be around. He still shares the pervertedness and ambition as normal Keiichi, but this time, he uses it for bad deeds. Dark Keiichi enjoys toying with people's lives, and he will not hesitate to hurt others, despite his fun personality.