Hitachibo Kaison (常陸坊海尊)
Kaison HITACHIBO (the date of birth and death unknown) is a legendary person whose name appears in "Genpei Seisui ki" (Rise and Fall of the Minamoto and the Taira clans), "Gikeiki" (a military epic about the life of Yoshitsune), and "Heike Monogatari" (The tale of the Heike), and is said to be a Buddhist priest at the Onjo-ji Temple or Mt. Hiei.
After becoming a retainer of Yoshitsune MINAMOTO, Kaison accompanied the flight of Yoshitsune and his party from Kyoto together with Musashibo Benkei and other retainers. In the Battle of Koromo-gawa River against the army of FUJIWARA no Yasuhira in Hiraizumi in Oshu (Northern Honshu, the region encompassing Mutsu and Dewa provinces) where Yoshitsune died, Kaison was said to survive because he and some other retainers of Yoshitsune visited a temple in the mountain.
There is a legend that Kaison became immortal (survived over 400 years, although his date of birth and death unknown) and told people the Genpei War or the Legend of Yoshitsune so vividly as if he saw such incidents with his own eyes.