For our first installment I'm going to go with the obvious and necessary choice of Darkness from Labyrinth Legend.
They could not have picked a better actor to play this demon. It's a scenery chewing character, and Tim Curry can gnaw it with the best of them! Darkness makes for a great BBEG
Lord of Darkness
Armor Class: 3
Hit Dice: 12
(L)
Move: 180' (60')
Attacks: 1 gore/1 weapon
Damage: 2d6+2
No. Appearing: 1
Save As: C12
Morale: 12
Treasure Type: G
Intelligence: 16
Alignment:Chaotic
XP Value: 4,750
Monster Type: Planar Monster, Enchanted (Unique)
The being known as the Lord of Darkness, or simply Darkness, is the spawn and champion of a Chaotic Immortal known as Nox who desired to see the world shrouded in perpetual night and winter. Darkness appears as a 9' tall satyr with red skin, black fur, and massive curving horns. He wears a sleeveless black robe, and carries a black staff.
Darkness commands a horde of corrupted goblins and other foul beings that he uses as his hands, eyes, and ears on the surface world. Darkness suffers 2d8 points of damage for every round that he is exposed to sunlight due to his deep connection to Nox.
In addition to his natural strength Darkness is capable of using the following powers 3 times/day: Charm Person, Cause Fear, Detect Good (Innocence), Blight. He can also use the following powers 2 times/day: Know Alignment, Produce Flame, Curse. The mere presence of Darkness causes creatures of less than 4HD to automatically make a morale check or be cowed into inaction. Darkness is immune to Sleep, Charm, and Hold spells, Fire, Cold and weapons of less than +2 enchantment.
Credit: about-world-religions.blogspot.com