Astaroth, the Betrayer

Astaroth is the demon lord of betrayal and manic paranoia, they are often associated with serpents and other venomous creatures. Unlike the more overt demon lords, the influence of Astaroth's corruption is quiet, lingering beneath the surface until its target is weakened or unsuspecting.
The Lord of Betrayal is said to reside in the The Writhing Chaos with the other demon lords, but none have yet found their domain.
Astaroth makes judicious use of all manner of fiends, devils and demons, but their most powerful agents are typically the serpentine marilith demons.