The lore in shorts :

in the longest day of the 1000th year where Nightmare moon came back from the moon, she actually won with celestia (MLP did her dirty just bc its a kids show lol) imprisoned HER on the moon, and hid elements of harmony or did sm with them so twilight wouldn't find them

Nightmare moon from now on rules the equestria, while twilight n her riends are trying to think of a way to defeat her

while my ponysona started being interested by the new ruler, she came to her and asked if she could learn magic by her side

Nightmare moon agreed ig and my sona started to learn her spells etc. xd

and after a longer while she could make my sona an alicorn so I'd help her with some duties or deal with twilight n her friends

I haven't driven extra deep into mlp lore so the storyy isn't perfect for now

my fursona's ref sheet