Although he is not as social as some others, Yosetsu is foul-mouthed and tense, except for serious or life-or-death situations, in which he becomes very easily startled and much more talkative, although he retains his harsh way of speech. Yosetsu's Quirk gives him the ability to fuse objects together at an atomic level, although he needs to be touching both objects in order to fuse them.[2] This Quirk is effective on both organic and inorganic material.