While a Soul Reaper like Ichigo and the others, he is not a part of the Thirteen Court Guard Squads. Instead, he whiles his life away in the World of the Living as a simple, lowly merchant running a small-time candy shop. He looks rather shady at first glance, but he is in actuality an extremely cautious man with an outstanding intellect. In fact, before he had traveled to the Sky Realm, he had envisioned and planned for no small number of contingencies.
He has a Zanpakuto, but because he has not revealed it during the battles with Sakunagi, its effects are still unknown.
In the past, he had served as the captain of Squad 12 of the Thirteen Court Guard Squads as well as chief of the Department of Research and Development, making him Mayuri Kurotsuchi's former superior. Perhaps unsurprisingly, he had excelled in developing medicines and analyzing his opponents' abilities—just like Mayuri.
