Reycom and Hosokawa, despite thinking of each other as tools, seem to have a good relationship with each other. Their tactic is to freeze the opponent and grab their spellbook, which works well.
Reycom is a heartless Mamodo kid. Reycom met Hosokawa while he was on his daily run, as he was eating the frozen fish. Reycom then stuck with him until he was fired from his job. Sensing his opportunity, he gave him the book. They were partners from then on. When describing each other in episode 5, Reycom said that he liked every rotten thing that Hosokawa had done, as it made him stronger. When his book was burned, he didn't bother to say goodbye to Hosokawa, but tried frantically to put his spellbook out, showing how their relationship was meaningless to him.
Hosokawa was once a deliveryman on the Mochinoki docks. After finding Reycom in one of the warehouses, he took care of him like he was his child. After being introduced to the spellbook, this relationship deteriorated. Hosokawa described Reycom in episode 5 as "his tool", and was so obsessed with this power that he wanted two Mamodo, targeting Zatch as his other Mamodo. After Reycom's book was destroyed, he supposedly went to jail.