Sawol is a refugee who lives with Seulah Jang as her younger sister to replace Seulah's dead brother; as Sawol looks similar to Seulah's dead brother due to having heterochromia. Sawol aspires to become a delivery agent so that she can protect her family, following her late brother's dream to protect Sawol. Her role model is knight 5-8. Sawol is capable of fighting in self-defense.

Spoiler

Sawol has a special ability where she can make her bone grow around her skin, allowing her to fight much stronger opponents and win against them. She eventually becomes the first female delivery agent.