User blog comment:Jopjopjop/Volume 20 Spoilers/@comment-24173056-20150720174044/@comment-24.149.42.183-20150721194801

Reason: he was investigating WHAT THE FUCK occured around the death of his cousin Cleria. You could comment that Rias's relationship with Issei is a less fatal repeat of Cleria's romance with Masaomi.