The Prompt Cupboard

MoD!Harry & HufflepuffCup!Tom raise Teddy and Delphi in an alternate universe

In one world, Harry Potter became immortal on a technicality. When this is discovered shortly after the Battle of Hogwarts, nobody takes it very well, and he inadvertently draws on his new abilities when he is attacked whilst holding his godson.

In another, the Tom Riddle residing in Hufflepuff's cup is horrified to see a Bellatrix pregnant with his child enter her vault to move him to Malfoy Manor, and even more disgusted to see the Voldemort he had become. The only thing he can do is wait for his child to be born and devise an escape in the process.

In this one, as the corpse of Lord Voldemort hits the ground and a Toddler Harry perishes opposite, they disappear, leaving two men holding infants awkwardly looking at each other across a trashed nursery and a dead Lily Potter.