As a baby, Discord was abandoned by his mother and left behind to be raised by another. Princess Celestia and Princess Luna found him and raised him. While Princess Celestia was busy, Luna took care of the Draconequus who began to see her as his mother. Many ponies feared Discord for his strange appearance and magic which he had little control over.

After Luna was banished, Celestia started taking care of the young Draconequus but due to fear of others judging him, he concealed his true form and asked Celestia to make others forget what he was, she reluctantly agreed and now, no one could remember what Discord was.

Years later, a unicorn tells Celestia of the coming return of Nightmare Moon so she sends her and a disguised Discord to Ponyville to make friends. Will they?

This is a possible retelling of MLP Friendship is magic but the Discord in the entire series. This was inspired by Hero by NalaxSimba.
https://www.fimfiction.net/story/284345/hero