thelightfang

Well, the newly possessed have eyes that are slightly red due to the entity's presence within their bodys. However, this usually goes away after a few days. The possessed also normally don't speak with normal voice tones. The voice gets slightly deeper. And the final thing to look out for is uncontrolled muscle spasms. These occur at first due to the body's original occupant trying to take back control but may continue on if the individual is strong enough to keep resisting the entity's control.

Hope that helps