Holger is a minor character in Beastars, working as a tattoo artist in a shop located near the Black Market. He is an adult sloth with a medium height and a slightly stout build. His fur is rough and marked with light spots on his face and darker spots around his small, beady eyes and ears. He possesses a long, thick neck and a rounded head, and is noted for his permanent, wide smile which gives him a somewhat meek or silly expression. His arms and legs are heavily decorated with tattoos, including the body of a snake winding around one arm and a tattoo that reads "kibin," meaning agility, on another. Long claws protrude from his fingers, and he typically wears a casual outfit consisting of a white tank top, light-colored pants, and white socks.

In terms of personality, Holger is consistently happy and carefree, maintaining this demeanor even when threatened. As is typical for a sloth, his movements and reactions are incredibly slow, a trait that his coworkers often joke about. His conversational responses are delayed to an extreme degree; he is known to respond to a customer's words approximately twelve hours after they were spoken. This physical limitation has a darkly humorous consequence, as enough animals have died from blood loss due to the slow pace of his tattooing that the other animals in the shop refer to him as a "psychopathic killer".

Holger's primary role in the story is directly tied to one of its main antagonists, Melon, for whom he is the exclusive tattoo artist. This relationship forms the core of his involvement in the plot. The protagonist, Legoshi, discovers Holger's shop and realizes that by listening to Holger's half of a conversation, he can indirectly gather information on Melon, as Holger is still responding to things Melon said hours earlier. Legoshi listens as Holger speaks to the absent Melon, asking if Melon feels worried, afraid, or lonely, and expressing a wish that someone could understand him. This prompts Legoshi to feel a sense of pity for Melon. However, it is later revealed that Melon was aware of Legoshi's presence the entire time and used Holger's predictable, delayed responses to set a trap, laughing at how easily Legoshi was deceived by the sloth's words. In a bonus content page, it is also revealed that Holger realized Legoshi was watching him but chose not to say anything at that moment.

A notable aspect of Holger's abilities relates to his profession. Despite his extreme slowness, he is capable of creating intricate tattoos. His unique biology also appears to grant him a level of patience and perception; his delayed reactions allow conversations to stretch over many hours, and he possesses an awareness of his surroundings, such as noticing when he is being observed. Holger is also notable for being one of the few herbivores known to work within the dangerous environment of the Black Market.