When was Blue Exorcist published?
Blue Exorcist
A spin-off focused on Rin's brother Yukio is running on Jump SQ.19, titled Salaryman Exorcist: The Sorrows of Yukio Okumura(サラリーマン祓魔師 奥村雪男の哀愁,Salaryman Futsumashi Okumura Yukio no Aishū). It is also written by Kazue Kato, but with illustrations by Minoru Sasaki.