Hakutaku

Hakutaku is a Celestial Beast and pharmacist living in Togenkyo at the Sentou Farm in Heaven. He took in Momotaro as his assistant and has been imparting his skills to the exogre slayer ever since. He dwells among rabbits who also learn medical skills from him and aid him in preparation of herbal concoctions. Hoozuki is his archnemesis despite their many similarities. Source: Hoozuki no Reitetsu Wikia