Rumia is Sistine's best friend who lives with her family. She is close to Glenn, who often treats her well, in contrast to the teasing that Sistine faces from him.
Rumia's real identity is the Princess Ermiana El Kel Alzano, the "cursed" princess who was supposed to die three years ago. She possesses a high level of spiritual essence, marking her a primary target pose by greedy scientists. She remembered Glenn being the one who saved her life when he was the infamous assassin named "The Fool" three years ago.