The Eminence in Shadow, Vol. 14 (manga)

"What a fine night it is to cut the past loose." Cid's enjoyed his little visit to his old stomping grounds in post-apocalyptic Japan, but he beat the big monster already, and all the secret conspiracies around here seem to be falling apart, so it's probably about time he returned to the awesome fantasy world he came from. Just one hitch, though-in the end, just what was his former classmate Akane's deal?