User blog comment:B214/Season 3 confirmed!!!!!!/@comment-107.10.155.255-20141222235334/@comment-16281343-20141223001620

Wrong. Reread the novels to correct your info.

Ravel didn't join any clan. She was just entrusted to Issei by her mother in the hopes of her becoming Issei's servant in the future. Then, she became Issei's manager upon Sirzech's request.