Karaka

Karaka is a Ranker and Slayer in FUG. His secret hideout is located on the 97th Floor and also Karaka's Heart. Karaka, similar to Baam the protagonist, was groomed and trained under Ha Jinsung to be one of the thirteen Slayers of FUG, quickly rising through the ranks and making a name for himself in the Tower despite his young age relative to others. He has never been shown without a full-body armor on covering even his entire head, supposedly to hide his face as he only allows a few selective individuals to observe his true appearance. Although Karaka usually shows his cold and ruthless side, the Slayer can be quite loyal and caring, expressing great anger when his master was abducted and went so far as risk his life and team up with an enemy-Baam himself-in order to rescue Jinsung. Karaka's ultimate goal is to slay King Jahad and the Ten Great Family Leaders, overthrowing their very dominance over the Tower.

(Source: Wiki)