High School DxD, Vol. 7 by Ichiei Ishibumi (Paperback, 2015)

A conference between devils, angels, and fallen angels?! Kuou Private Academy will never be the same!!Devil King Sirzechs pays a visit to the Hyoudou household, and he's got some astonishing info for Issei and the gang! Later, the beautiful swordswoman Xenovia too has a shock in store for Issei when she asks him a question that's been on her mind: 'Will you have a child with me?'......Can she be serious?!