[Maybe it's easy for a vampire like Ren to notice a person entering the stables even if that person does so very quietly, not offering a word in greeting (and maybe it's easy to tell that person isn't quite human).
Sebastian had an errand in here, but he stops as he sees Ren petting the horses. Instead he lingers by the door, watching the bonding exercise with a thoughtful expression, as if not wanting to spook the animals or ruin the moment.]