Twice has a very unique personality: He's explosive, lively, and comes across as having a very comedic demeanor, enjoying assuming dramatic poses and eccentric facial expressions. Twice constantly contradicts itself, making one statement in one voice and then immediately say the opposite in another voice. For example, he insulted Dabi and then praised him in the following sentence.[3]

Twice knows he is deranged and embraces it as a villain. Jin is actually much more complex than he first appears: He believes understanding your own identity is the most important aspect in life, joining the League of Villains because they accepted his craziness and made him feel comfortable in his own skin.

Without his mask, Jin suffers more heavily from his dissociate identity disorder: While masked, Twice contradicts himself and acts completely natural about it, but without it his split personalities argue with each other. He goes into a panic and threatens to "split" until he puts his mask back on and becomes "whole". Jin's identity crisis stems from a tragic accident that drove him to insanity, changing his overbearing and lazy previous persona. He has a strong self-conflict over who he actually is and believes that he might be a clone that had killed the original.[4]