Jindaiko no Raiden (陣太鼓の雷電, "War Drums of Thunder and Lightning") is the Zanpakutō Spirit belonging to the infamous Shinigami, Eri Fujiwara. In contrast to normal Zanpakutō and even Zanpakutō with dual spirits, Jindaiko no Raiden is capable of transforming into a second form of a giant snake, which somewhat hints at Jindaiko no Raiden's most powerful ability, and is the reasoning behind his masters nickname, "Jūsanseiza's Blue Serpent".