Tsuchinoko is the deceased great serpent king who was defeated in battle centuries ago by the warlord, Gunshin, after a failed attempt to invade the Eastern Lands. The legendary sword, Kusanagi, was then forged from his fang.
- According to Japanese myth, the god Susanoo, retrieved the sword, Kusanagi-no-Tsurugi, after cutting off the fourth tail of Yamata-no-Orochi, a giant, eight-headed serpent and discovering it inside. The weapon was later given to the goddess Amaterasu to settle an old grievance.
- In Japan, the tsuchinoko is a mythical snake-like cryptid creature, described as being between 30 to 80 centimeters long, with fangs and venom similar to that of a viper's. They also have the ability to speak and a propensity for lying.