I cut this part purposely short since I'll post the ending tomorrow.

Maid,

Does he really have to go back that far?

Well, actually, as long as it is after he kisses her as the Blur it will be okay. It was the kiss that was the giveaway.

He definitely has to go back before he left -- since when he returned, he had amnesia, so that wouldn't work.

Don't want to say more... hope you like the ending!