Once upon a legend there were 4 kinds of guardians Shikuro guardians,the shikuro guardians are the guardians that keep the world going,the Ai guardians are the guardians of love,the Memori guardians are the guardians that keeps a memory kept the're the once who woud'nt let a single memory forgoten,The Ryūgen Guardians aren't really a guardian there the who spread chaos,hate everything bad (read for more)
6 parts