I just realized Belkar is paler from #879 through #939. Likewise Elan is paler in Panel 7 and Panel 6.
I see it as basically a rapid aging spell so I don't think it would disrupt the enslavement aspect, though I suppose Malack could've actually made the spell to make sure his spawn's spawn directly obey him upon rising.
But the first panels of #1087 and #1124 make me think it was the 2 female vampires who cast all the quick-rising spells anyway.