Seekers

Seekers are agents of the Adumbrali. They appear as unusually perfect humans.

In the RPG...

Seekers have the ability to hypnotise people, which sends the victim's mind to the Adumbrali's dimension. They have a 73% chance of succeeding in this against an average human. All of their stats are the same as a human's, except for INT, POW, and APP. POW and APP are higher, while INT just has an increased range. This means that 5% of Seekers are more intelligent than the smartest human, but also that 2% are less intelligent than the dumbest one. I guess the Adumbrali creation process could use some tweaking. 

In a video game...

Because they appear as regular humans, Seekers could easily work in a game. They would be of no use, however, unless the Adumbrali were also included.

In a film...

As above, a film featuring Seekers would have to ultimately feature Adumbrali—a package deal. Being human, the Seekers themselves might not come across as much of a threat, so it would all hinge on how scary the Adumbrali were portrayed.