i don’t know how serleil or runas would end up in the shadowIands (since they’d both be appearing there as mortals much like the maw walker/player character) but i think it would be really funny if they were requested to come across the veil to help with the venthyr rebellion by the virtue of “hey you helped successfully overthrow one power-hungry corrupt leader, can you come help with another one?”
the area around castle nathria feels a lot like questing in suramar city did too, with the helpful npcs being scattered throughout a vast (and very mazelike) city filled with hostile mobs that you have to dodge to get places (although there was a disguise to get past some of the mobs in suramar, there isn’t one to bypass them around castle nathria)
they would both fit in really well with the covenant from what i’ve heard of the ember court sanctum ability too, party planning for a bunch of snarky vampires would be RIGHT up runas’s alley. serleil would probably be less thrilled by having to coordinate things but i can’t imagine venthyr court parties being too dissimilar from lady lunastre’s parties