BackgroundEditReplica was created by Yūgo Kuga. When Yūgo told Yūma to stay behind, Yūma decided to go anyway, but Replica said he shouldn't, to Yūma replies by saying he'll go unnoticed. Replica is the one who told Yūma to come to Human World to see his father's friend. His real motive was to do something about Yūma's dying body.
Replica is first seen in Chapter 1, after Yūma is hit by a car. When Yūma was asked where he lived, Replica gave him the address. He then says that if he keeps getting hurt like that, his body will be severely damaged, and Yūma tells him that if he worries too much, that'll happen again. Replica then tells Yūma he's 25 minutes late for school, to which Yūma replies in disbelief, saying it's impossible. Yūma then asks Replica if he can use his trigger, which Replica denies, saying he's the one who decides when Yūma can use his Trigger. Yūma then says he's gonna leave, and Replica says he should be careful with what he says. Later, when the Bamster attacks the bullies that were bullying Yūma and Osamu, Yūma asks again if he can use his Trigger. Replica allows him, again saying Yūma's the one who decides when he can use his trigger.
On the next day, while Osamu explains Yūma on how not to gain attention, Replica tells Yūma that Osamu is right and getting attention from Border would not be good for him. Before Yūma challenges the Bullies in the school's roof, he says Japan is very nice to mean people, and Replica says it's because there aren't many people doing bad things.