Susumu is small boy with light-coloured eyes, long wavy hair which covers his right eye, and wears a large fur coat, presumably to cover the marks on his body from his mother's abuse.
Susumu had a kind but timid personality, showing great fear towards his "mother". He was also good friends with Tare.
Susumu is seen playing at a park with Tare. As it gets dark, Tare says that they should leave, but Susumu says that he would rather stay at the park. He says that his mother used to be nice, but recently purchased a big dog, Jiro, who she commands to attack him, and then locks him in a small room. Susumu has told his father, but his father doesn't believe him. Because she only acts this way when his father is at work, Susumu goes out of his way not to go home before his father. Susumu tells Tare that there has been a large increase of parents killing their children, and fears that the same will happen to him.
Tare says that Susumu could stay with his family for a while. However, on the way home, they encounter Susumu's mother with Jiro on a leash. Tare calls her out on her abuse of her son, but she claims that he just makes these stories up as an excuse to stay over friends' houses. Susumu confirms what his mother says, and after his mother says that his father has come home early, he decides to go home with her instead of staying at the Makimura's. Susumu apologises for lying before heading off with her.
Once they arrive home, his mother reveals that she lied about his father being home, and sics Jiro on him to punish him for telling Tare about her. Just as Jiro bares his teeth, Susumu's father walks in. Susumu runs to his father crying for help, only for his father to remove his hat, revealing the head of a demon. The three of them then kill and eat Susumu, only leaving his head behind.
- Both the concept and character of Susumu originally appeared in a short manga by Go Nagai called Susumu-chan's Dai Shock, which followed a bizarre phenomena of mother killing their children.
- Susumu is a minor supporting character in the manga Shin Mazinger ZERO . He mother is also seen, but only her body.