Asanuma (浅沼, Asanuma) is the driver of the human trafficking trio that delivers people to Yagiri Pharmaceuticals for their human experiments. His partners are Morita and Kanazawa. All three are members of the Dollars.
Asanuma is an overweight man of average height. He has short spiky scruffy black hair and has pronounced lips. He has stubble on his chin and has small black eyes, typically he is seen wearing a navy blue shirt under a blue track jacket with a white stripe going down the sleeves. He also wears long beige shorts.
Asanuma is a coward; always the last one remaining after his two companions have been incapacitated, he never hesitates to whine and beg to be spared.
Mika Harima Arc
Asanuma is an accomplice in the kidnapping of Rio Kamichika. After Morita leads Rio to the back of the van and Kanazawa drugs her with chloroform, they drive to a parking garage and wait for her buyer to arrive. The Black Rider arrives where their buyer does not, and, when Kanazawa attacks, Celty rams his head into a concrete wall with her motorcycle.
Frightened, Asanuma climbs back into the van and starts its engine while Morita jumps into the back. Morita tazes Celty when she drags him outside, but she swiftly recovers and slams his head into the back windshield, knocking him out. Asanuma drives away in a panic, and Celty takes chase; eventually, he comes to an abrupt stop that causes Celty to crash into the van's back and fall off her bike. Her helmet falls off upon impact with the pavement, revealing her lack of a head. She stands, summons a shadowy scythe, and renders Asanuma unconscious with a single slash.
Asanuma and his crew later kidnap Kaztano from a building where he and other undocumented immigrants reside. While they manage to force Kaztano into their van without much trouble, Kanazawa spills the chloroform on himself, resulting in all three kidnappers becoming sleepy. On Kaztano's suggestion, Asanuma and Morita drop Kanazawa off in some bushes so as to make themselves less drowsy.
As Kanazawa still has Kazutano's cell phone in his pocket, Kyouhei's gang are able to track Kaztano down, with Saburo soon in hot pursuit of Asanuma's van. With Celty's help, Kyouhei's gang manages to corner the kidnappers and rescue Kaztano. Asanuma tries to escape by climbing a fence to escape, but Kyouhei pulls him down and leaves his fate to Walker Yumasaki and Erika Karisawa. Though Asanuma refuses to talk at first, a torture session with Walker and Erika leads him to share information on the human experiments conducted by Yagiri Pharmaceuticals.
Asanuma is the leader of the group of thugs that kidnaps Non, Rio Kamichika, and their friends. After abducting the girls, he orders Hiroshi and two other men to stay behind and beat up Mikado Ryuugamine to prevent the younger boy from contacting the police.
He presents the hostage girls before Kyouhei and Chikage Rokujou immediately after their fight at Raira Academy Field Two. He confronts Kyouhei on his position within the Dollars and attempts to attack him with a knife but is quickly knocked out by Chikage. When he comes to several minutes later, he is being questioned about the kidnappings by Shizuo, and, responding violently, gets his arm broken and is thrown into a fence thirty feet away.
- He is not given a name in the first light novel, but the same thug who hits Celty with his convertible in the parking garage is questioned and narrowly escapes being tortured by Walker and Erika the next day.