Rajin (ラジン) is one of the most trusted members of King Bell's Royal Knights, if not the most. When Zeno Bell was three years old, Rajin was entrusted to give him special training by King Bell himself. He is often worried about Zeno, referring to him as "Prince Zeno." At the time of Zeno's training, he was held the rank of Lieutenant General (中将, Chūjō).
He was seen in Zeno's flashback in chapter 261 of the manga.
- Many unofficial scanlations of the manga often transliterate Rajin's rank (中将, Chūjō) as Captain when Chūjō translates to Lieutenant General. It's possible that the military ranking system in Mamodo World is based on the Imperial Japanese Army's ranking system from World War II.