Hayasaka is a rather anxious and submissive man that periodically speaks in a stutter, usually accompanied by nervous laughter.

Afraid of the monsters that come to attack, he does his best to help fend them off with the others.

His kindness and humanity is expressed with how distraught he is when Gin risks his life to save him; considering as a Dummy, his life isn't destructible.

Hayasaka's victim video is found in Miley's Room, unlike the rest of the victim videos which were sold in the Prize Exchange. He appeared to be one of the participants that died in the First Trial, though it's unknown how he was supposed to escape and it appeared to be an execution instead. Before he was killed via a swinging blade, he curses out Sara's name and the organization running the death game. 

Hayasaka is paired up with Gin Ibushi once he is revived for the sub-game. Like all of the other dolls, he awoke with knowledge of the situation and one piece of special information, though unaware of the circumstances of his death barring the victim video he appears in. Hayasaka, the moment he is paired with Gin, states that since Gin is a child, he will have to protect him; but Gin reverses this, claiming that Hayasaka looks weak. The power dynamic quickly shifts towards Gin having the upper hand and the two bond slightly throughout the early phases of the chapter. Once the locker room is reached, Shunsuke is unexpectedly brought to the ceiling forcefully by magnets in his collar, essentially nearly hanging him, but is soon freed.