Arbiter, also called アービタ (Ābita), commands the Flame Spear Mercenary Corps, focusing on merchant escort missions. He once held the rank of captain within the Felskeilo Knights.

He possesses black hair cut to ear length and eyes that are blue or green. Arbiter is an adult human male with no animal traits.

Professionally dependable, he nonetheless displays a surge of impulsive challenge during moments of high tension, frequently provoking mock battles against Cayna. These encounters occasionally involve outside interference; Kee is cited as having debuffed him in one instance, while the manga adaptation credits Lopus Harvey with a similar action.