He is a member of the magical circus known as "Pale Moon". Of demon and warbeast descent, he has better control of mana compared to ordinary warbeasts, and specializes in juggling of his dear knives.
Whenever he performs juggling, he casts sharpening magic on the knives' edges. His fingers would have been cut off if they touched the edges in this state, with sharpness proven by experiments showing that the knives can even cut iron plates into two. Nonetheless, he has not even made one mistake in all of his public performances, numbering hundreds. His extraordinary popularity, standing out from the many jugglers of the circus, doesn't only come from his graceful appearance, but also his techniques succeeding in these life-risking performances for sure.
By the way, a knife maniac---he is not exactly something like this. But, he calls his dear knives with names like "Salen", "Break" and "Shy", and ecstatically sharpens his knives on a grindstone every day, making almost every circus member mistake him for a knife maniac.