Onmyou Taisenki S01 E22 Seal Engraved on the Heart

Riku and Kogenta arrive in a tranquil part of the Fukumaden. Riku feels very nostalgic about this place. But a Chi-ryuu Toujinshi, Gaitatsu and his Shikigami, Aogane no Nanaya, come and decide to destroy the place in search of the Toujin stone.