For the Consort!AU(the one where Reader is married to Belos - calling it that now), I can see Belos giving Reader a ring that tracks their movement. To know their location in the castle OR if the beloved Reader is somehow out of the castle.
Oh, you know that fucker would do that. It'll kinda be like the Marauder's Map from HP, but he can only track Beloved but if they're near anyone, the person's name shows up near them.
He's often chasing Adrian away from his Beloved since Adrian adores flirting with them and he sees it as a game knowing Belos won't kill him because he's needed for the Day of Unity. Belos is furious that a witch thinks it's okay to mess with his Beloved.
He has a heart attack when "Luz Noceda" pops up near them.











