There is a reason why dark magic is forbidden unfortunately Twilight finds out why first hoof.
Animation is by Derek pony: https://www.youtube.com/channel/UCiIDamAuKhOc0ZH_ojxePnQ
Intro music is by Reverb Brony:https://www.youtube.com/channel/UCAQOqHJvY7iI_uw4u2TNi-w
Music by Myuuji: https://www.youtube.com/user/myuuji
https://www.youtube.com/watch?v=t2seD20g9cA
link to story:http://www.fimfiction.net/story/340067/descent