Dangerous, yes, but only at certain moments. The dragon sniffs Adia, remembering her scent from mere months ago, when he was just a baby Deino. He grunts a little, nudging her back with his snout, making sure she gets into the room. Sara walks over to the door and locks it shut, while Jeff watches with emotionless eyes.

"Let's go, Master Nyarlathotep." Sara starts walking towards the staircase and Jeff follows her, now being addressed by his new name. It seems like Jeff truly is gone in favor of his body being controlled by an elder god.

As for Hydriegon, the dragon lays his head next to the door and sniffs loudly. Despite being there as an intimidating force, he doesn't want to leave Adia no matter what. He heard what Adia said and tries to do, which gives the dragon Pokemon some faith that she can bring his master back eventually.