Artemiy Artemiyevich Pinker

Artemiy Artemiyevich Pinker, better known as Che'nya, is a third-year student of Royal Sword Academy. He is a childhood friend of Riddle Rosehearts and Trey Clover. Che'nya's Unique Magic can make parts of his body disappear and reappear at will. However, it depends of his mood when using it. (Source: Twisted Wonderland Wiki)