A student and brother of Sae Shimada.

After the death of his parents, Shimada had to support his younger sister, taking on several part time jobs. One day he returned home and saw that his sister had been assulted. He went on a path of revenge to ensure his sisters desire for her killers to die. However, after learning the details concerning his sister's assault, he was thirsty for the blood of those responsible. He swore revenge and succeeded in murdering both her assaulter and Tatsumi, who watched and did nothing to interfere, only to die from an wound the assulter gave him.

At Queen Decim during a game of air hockey, Shimada learns that Tatsumi did nothing to save Shimada's sister, and willingly stabbed the pucks which were connected to Tatsumi's nerve, effectively causing a "Second death" for Tatsumi, despite the fact that he was told by Chiyuki that seeking revenge would send him to the void, never to be reincarnated or see his sister again.
(Source: Death Parade Wikia)