By a million in one chance, Fulgrim stumble into trans-dimensional before the Horus Heresy. Fulgrim is in Equestria, and before long, he got a pretty pretty makeover with Rarity…
 
Fulgrim : Pretty Xeno, you’re soo fabulous and perfect… thanks for the makeover.  
Rarity : it’s my pleasure Fulgrim Darling… You look soooooo fabulous now…  
Fulgrim : With this, you got my words that Equestria is under Emperor’s Children’s protection, I know, my daddy will be mad about it, but as long as you xenos don’t wander outside your star system, it would be all fine and pretty…  
Rarity : but what will happened if some other humans…  
Fulgrim : nah, you have my words, this world is perfection of beauty and too pretty to be stained by humans… This world is under protection of Emperor’s Children, Imperial colonies try to settle here will got their ass kicked.  
Rarity : Thank you Darling, that’s soo generous of you…