The Metamorphmagus and His Brother

The Potter surname was known at Hogwarts two years before The Boy Who Lived attended the school himself.

Lenox Potter, older brother of Harry Potter, who ended up in the care of the Weasley family when he was but three years old. Gifted with being a metamorphmagus the young Ravenclaw has to start his third year with Fred and George when Harry and Ron start their first year.

The only complication is that Harry has no idea who he is and it becomes Lex's internal battle to bond with the boy.

Inspired by kmbell92 and her Brotherhood series. I recommend the books!