Senkenteki

Senkenteki (先験的 senkenteki; Eng Lit Translation, "Transcendental,") is a spirit of an unknown race said to have stretched back as far as the Hakami. The origins, history, and knowledge of their culture is unknown as Senkenteki is the sole survivor of their race as well as the inheritor of their greatest teachings, arts and combat styles. He swore allegience to Sōsuke Aizen for a chance to avenge his people as well as reclaim the lost terrirories and world they once possessed.