^ He's drawing it for a, appropriately enough, Touma/Kaori fanfic by a fellow Pixiv member.
EDIT: Unrelated to that, different artist this time... but enough to make me post here again.
Spoiler for Responsibility:
Touma: "Respon...sibility..."
*Touma's imagination*
Kamijou/Kanzaki Jr. : "Papa, what's a [Fallen Angel Ero Maid?]"
*Kanzaki unsheathes her sword*
*Touma silent*
(Dialog bubble I don't know whose): Ah, yes...
inb4 'hey it's Hina!?'