At the end the guy gets his girl, but the process of doing so results in him being beheaded. It's the only way for him to remember everything, because when he gets stuck on a body he forgets everything since he became immortal. Show ends with the naked girl cradling his severed head in her lap.
It's clearly School Days. Someone even put "Nice Boat" in there already.
Nanoha..."♪If I can make my way to the other side of sorrow~♪
♪Kanashimi no mukou he to tadoritsukerunara~♪"At last... we're alone together.* Deck of the Asura
