 He was born sharing his body with a symbiotic being that usually conceals itself so that only its closed eyes are visible as a wart/growth on Tenzen's ears.The creature awakens whenever Tenzen is wounded or killed, moving through his body to regenerate him by "eating" his wounds, thereby restoring whatever ravages of time or battle Tenzen might experience.Thanks to his powers, by the time of Basilisk's beginning, Tenzen was already well over 200 years old though physically he looks no older than 30.