Searching for HP fic where Lockhart defended Hogwarts alone

There was this fic i read years ago. I think it was MOD Harry but i can be completely wrong. Maybe Death asked main character to possess Lockhart and save the magical world because fate was ruined there. And so Lockhart fights Voldy and everyone alone and wins, dying at the end from injuries.

Anyone knows the title of this fic? This was like in late chapters at the end of story, not the main story at all. Just small bonus side quest.