Yūma is shorter than the average for his age range. He has white hair and red eyes. It is later revealed that his hair was originally black and his body had stopped growing since he was 11 years old because it was made out of trion, thus explained his short stature. 

In Black Trigger mode, Yūma gains a black jumpsuit which Replica can fuse itself with. In C-rank trion body, unlike most other trainees, he gains an all-black uniform, instead of the classical all-white one; it has a black jacket 