I noticed that when infernal spirits follow you into the workplace unrestrained, (or any social setting) the behaviors of people change noticeably. This is because their astral presence actively affects peoples minds to act in certain ways that their energy favors. This is how the infernal spirits vampirize. Its not just astral vamping. It can be attention, social, sexual, willpower, etc.
I’ve noticed demons work on a more mental level first and physical second. (Sonce they are astral beings) So the most noticeable initial changes are gonna be in how you think and navigate life, as well as how people perceive you.