Mimics (The Formless)
Mimic, often called the formless because it is said that nobody alive has seen their real face. Rumours say that the mimic will show that to its victim, moments before it kills and replaces them.
Ever noticed somebody suddenly become slightly different? They look the same, they act the same (mostly), they know you but sometimes...they seem to have forgotten things, nothing vital or terribly important but little details? Then maybe your friend is dead and a mimic is watching you. Beware because the dead whom they replace are never the mimic's true target, that was simply done to allow it to get close enough.
Like striga-strain, mimics are pathovores however for a mimic, emotions are the main course, no the entree as for strigoi. Mimics will suck the victim dry of everything which makes them - well - them. Memories, secrets, everything. Do you know the popular saying about one's life "flashing before one's eyes" at the point of death? The mimic waits for that and drinks it down like fine wine. The mimic will then sleep in order to affect the physical changes and integrate memories and personality, often in presence of the recently-deceased. Once ready they put on the dead's clothes and install themselves in their lives.
Mimics are completely undetectable by today's technology. Some sensitives and animals can detect them or at least feel terribly uncomfortable in the presence of one; something indefinable just feels wrong. Beware because if the mimic's mission is important enough, they will find ways and reasons to eliminate anyone who even looks at them funny.