The year is 2020, discord defeated celestia and Luna 5 years ago and ruled equestria with an iron fist, as twilight had lost her friends and been "discorded" she began to learn about the elements of disharmony and learned to harness it and the dark arts of magic. After harnessing the elements of disharmony she killed discord and became supreme queen twilight sparkle. You are from an alternate reality were discord was defeated (normal timeline) and equestria still had celestia and Luna, a mysterious stallion then brought you and your friends here to help defeat the corrupt twilight sparkle and return equestria to normal

So you can use an oc but try to give a little bit of info like a specialty they have e.g "fire spark specialises in stealth and magic" so I will see you in the role play