The Shitōshin (四闘神, "Four War God") were four powerful demons who attacked the island of Hōraijima after its time barrier weakened. Despite their success in routing the inhabitants of the island, the priestess Kanade sealed their Spheres of Power into a comb box and lept into the Cauldron of Resonance. Unable to leave the island without their power, the Four War Gods took over Hōraijima and sacrificed half-demons in the cauldron to release a portion of their power to sustain themselves. They are eventually defeated by Sesshōmaru (Kyōra), Sango (Jūra) and Inuyasha (Ryūra and Gōra). Their true form destroyed forever by Inuyasha with Adamant Backlash Wave. They are based on the Four Celestial Animals. The members and their respective animals are Ryūra (Dragon), Kyōra (Phoenix), Jūra (Tiger), and Gōra (Tortoise), based on the four Chinese constellations.
Trivia
Each of the War Gods names end with the kanji '羅'(Ra), which translates to 'Compass'. This is a reference to them being based on the Four Celestial Animals.
They are the second group to follow the four celestial animal trope. The other group is a clan of demon ninja named after them: Genbu, Seiryu, Suzaku, and Byakko.