Heigo Hamaguchi is a Japanese retired professional wrestler, better known by the ring name Animal Hamaguchi . During his career he was recognized as a talented tag team wrestler despite his relatively small size for a heavyweight, and today he is recognized as a trainer in both professional and amateur wrestling. He is the father of freestyle wrestler Kyoko Hamaguchi.

Shinjiro Otani is a Japanese semi-retired professional wrestler and the current acting president of Pro Wrestling Zero1 (Zero1). He is currently inactive from pro-wrestling competition due to a cervical spine injury sustained in April 2022. A product of the New Japan Pro Wrestling (NJPW) dojo, Otani is best known for his longtime association with Zero1, a promotion he founded in 2001 along with Shinya Hashimoto.