The Tokyo Oniwaban group is led by Aoshi (who leads the entire Oniwaban in every city, but this is his main force). It used to be much larger, but after the war most of the Oniwaban returned to normal lives. These four could not, having sacrificed normal appearance and skills to become better fires, and so Aoshi remained with them and they became a sort of mercenary group, looking only for the reputation of being strongest. They are killed in season one, driving Aoshi to great mental anguish. They are hardened fighters, but they are loyal and evidently can be caring (at least to Misao...)
Names (left to right): Hyottoko, Beshimi, Shikijou, Hannya