Naberius

Neberius, also known as Cerberus or Cerebre, is a strong and powerful demon appearing as a black crow, raven, crane, or three-headed dog. In human form, he has deep green skin. He is a marquis of hell, commanding 19 legions.

When summoned, he speaks eloquently in a harsh voice and teaches of arts and sciences, particularly rhetoric. He plays a somewhat political role, keeping an eye on all that happens in the demon world, sort of like how police departments have an Internal Affairs office. He is also able to strip the dignities and honors of those who don't deserve them, or to provide or restore them for those who do, though this applies more to humans than demons.

Naberius is said to be very friendly and extremely fair. He maintains some connection to the underworld and has the power to raise the dead if necessary.

Rituals
To summon Naberius, one can put a red candle on a plank of wood from an ash tree and float it upon water, to represent Charon bringing souls to Cerberus.