A creature of old has been present in Equestria since the beginning of the rule of the alicorns, watching, waiting. He saw their fall and the sisters' rise to power. Now, for the first time in eons, he steps from watching and takes action.
Equestria has resources not found in any other dimension, so of course an alcoholic, mean-spirited scientist would get in on that and drag his grandson along for the ride.
MLP/Warhammer 40K crossover. Chaos Space Marines from the piratical 38th Company have engaged Tau forces around a planet rich with alien life, magic, and... friendship? I guess? Weird.
When the first Equestrian Lich King is in need of guidance, who better to help him than the second in command of the Azerothian Scourge? Follow Kel'Thuzad in his new unlife in the colorful world of Equus.
Twilight saved Chrysalis from a bitter end, thus changing her own fate and that of the Elements of Harmony. As she learns the power of redemption, Twilight gains power never before recorded in history. Equestria itself will never be the same.