Appearance
Dark haired, wears white shirt, seemed easy going at first.
Personality
He was initially a very kind individual. He was a very nervous, innocent boy and was shown to be friendly and trusting to others. He is strong and supportive towards those he cherishes, as he promised to protect his sisters after his parents died and took on several part time jobs to support her and ensure her happiness. He is also protective of her and when he discovered she was assaulted, he went on a path of revenge to ensure her desire of those involved in her assault to die was carried. However, after learning the details concerning his sister's assault, he was thirsty for the blood of those responsible. His easy agitation towards the taunting of the detective led to his downfall.
Background
His parents died in an accident, leaving him to support his younger sister Sae. He would cook breakfast for her and take care of her, even going so far to take several part time jobs such as a construction worker just to support her. Unfortunately, one day after returning home from work he saw that his sister had been assaulted.
Plot
Relationships
Sae Shimada
His sister whom he has cared for since his parents died. He would work late night part time jobs and cook for her and took care of her in place of his late parents. When he came home one day, he saw that she had been beaten with bruises and realized she had been assaulted. He swore revenge and succeeded in murdering both her assaulter and Tatsumi, who watched and did nothing to interfere.
Tatsumi
Initially, because the two had no memories the two were able to get along well. However, once both regain their memories Shimada became murderous towards Tatsumi after learning Tatsumi did nothing to save Shimada's sister, he 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. After stabbing Tatsumi, he essentially becomes the same as Tatsumi as he smiles and understands what Tatsumi meant when he said judging others and seeking revenge against those who are "wrong".
Chiyuki
She tried to warn Shimada against taking revenge against Tatsumi, as doing so would send him to the void never to see his sister again. She even purposely grabbed him from behind and held him back, and for a while he listened until Tatsumi continued to egg him on, effectively shutting out Chiyuki's words of seeking redemption and proceeding to "kill" Tatsumi a second time.
Decim
He acts as the arbiter for Shimada's judgement.