User blog comment:SonikkuAensland/(No official) Sophia and Cerberus Black Talk about - Dimension Bellum./@comment-24183810-20160706182028

I really should've mentioned this a while back, but Fallen Ones can infect others into becoming Fallen Ones themselves. The process is called a Dark Offering where the Fallen One inserts a portion of its Monstrum power into its victim, thus cursing him/her into succumbing as a Fallen One eventually. Cue Seigmar Umbra's victory quote against Semiramis for example:

"GivE...YOu....DaRk oFFeRIng!!!!"

Fallen Ones can do this to anybody, but their preferred targets for a Dark Offering are those who are formidably strong.