Drakel said
Nobody likes a Marry Sue.
It not like anyone can become a alicorn. Something to do with creating a super duper hard potion, having high magic level or something.
Really drakel Alicorn OC's are seen as marry sue bullshit in fan fiction.
Also should i mind you dragons are not even close to strongest thing in DnD.
If you want to get technical The Lich would be as they gain power at a huge rate over time.
In Planescape(DnD setting)
Despite being the strongest know lich(over 10 or more thousand years old) There was 1 thing even more power to the point of mary sue standards.
The lady of pain. Oh dear sweet mary sue, thou does not fuck with the lady of pain.
She has no stats, because you couldn't kill her if you try.
Mind you the lich that i talk about (could kill 4000 dragons with a wave of his hand) only lasted 5 minutes.
