Queen is one of the main protagonists in the series, and current Wild's league champion. She's a mixed martial artist and is seen to be proficient in nearly every form of martial arts so far. At first, Queen was cold to Song Jae Gu. But slowly she has warmed up to him and now (though she tries to hide it) tags along with Lee Moon Young and Choi Dal Dal when they follow Jae Gu to his part-time job and then to his home. It's been said that Queen has "conquered" the Taekwondo, Karate, Mixed Martial Arts and Kickboxing stages. Though it's unknown whether this is true.

Simca is a main supporting character in the series she is also known as the "Swallow". She is the secondary female protagonist of the series.

A mysterious albino girl that Ganta encountered during his first days as an inmate. Clothed only in a skin-tight bodysuit and muffly gloves, which conceals her heavily scarred skin, Shiro stands out among the other prisoners due to her bizarre appearance and mannerisms. To Ganta, Shiro's manner of speaking and acting remind him of a small child, even though Shiro is the same age as him. However, Shiro possesses inhuman physical abilities and has an intimate knowledge of the prison, having apparently lived there most of her life. From the beginning of the story it is made clear that, as children, Shiro and Ganta were close friends. Ganta, however, has no memories of his childhood, which greatly saddens and annoys Shiro.

Yoon In Gyi & Simca