Fallen Fifty

The 50 unknown deaths of The Battle of Hogwarts was the deaths of the people who were killed fighting Lord Voldemort and his Death Eaters besides Fred Weasley, Colin Creevey, and Remus and Nymphadora Lupin. It is likely most of them were adults as Harry Potter didn't see anyone he knew dead, besides those named. A the end of the Battle, all of the bodies were stacked together in the Great Hall. It is unknown what happened to their body's later.

Appearances
Harry Potter and the Deathly Hallows, Chapter 36