Lucius, Scorpius, Yaxley, Narcissa, Severus, Macnair, Nymphadora, Andromeda, Marvalo, Argus, (Mrs.) Norris, Nagini, Aberforth (Harry Potter)
Actually, Lucius is a derivative of Lucian, which is a derivative of Loukas (greek) and Lucas (forget) which translates directly to "Light".
I don't know if it was possibly mentioned, but the old, ancient names for demon lords and gods were pretty bad-ass and evil sounding. Mesopotamia and Africa come to mind.
i rather think my nick is sinister sounding
Abaddon - Lord of Destruction
Oh, so someone did.

Tiamat: A goddess who spawned serpents and dragons... "Tiamat is usually described as a
sea serpent or
dragon, however assyriologist
Alexander Heidel disagreed with this identification and argued that "dragon form can not be imputed to Tiamat with certainty". Other scholars have disregarded Heidel's argument,
Joseph Fontenrose in particular found it "not convincing" and concluded that "there is reason to believe that Tiamat was sometimes, not necessarily always, conceived as a dragoness".
[11] While the
Enûma Elish does not specifically state that Tiamat is a dragon, only that she gave
birth to dragons and
serpents among a more general list of monsters including
scorpion men and
merpeople, other sources containing the same myth do refer to her as a dragon."
Enki & Enlil: I put both of these together, because the mythology about them is convoluted. One story depicts Enki as the "villian" while another depicts Enlil as the "Villian". In either case, one tricked/overthrew the other -- because one was going to reveal to mankind that they are slaves (the proverbial apple from the tree of knowledge). I believe Enki and Enlil is the story where the idea of "angels vs fallen angels comes from. Enki being deity of water, intelligence, crafting and creation; Enlil being deity of the storm/wind.
Nergal: "god of plague, war, and the sun in its destructive capacity; later husband of
Ereshkigal: goddess of Irkalla, the Underworld"
Sin or Nanna: God of the moon
Asmodeus: Demon of wrath
Moloch: Molech, whose name probably derived from Melech “king” and Bosheth, “shame”, was one of the deities worshipped by the idolatrous Israelites. He was referred to as “the abomination of the children of Ammon” (1 Kings 11:7) and the primary means of worshiping him appears to be child sacrifice or “to pass through the fire.” Solomon was said to have built a temple to him.
Lillith: Demon of waste places. There is an old exorcism against her:
"You are bound and sealed,
all you demons and devils and liliths,
by that hard and strong,
mighty and powerful bond with which are tied Sison and Sisin….
The evil Lilith,
who causes the hearts of men to go astray
and appears in the dream of the night
and in the vision of hte day,
Who burns and casts down with nightmare,
attacks and kills children,
boys an girls.
She is conquered and sealed
away from the house
and from the threshold of Bahram-Gushnasp son of Ishtar-Nahid
by the talisman of Metatron,
the great prince
who is called the Great Healer of Mercy….
who vanquishes demons and devils,
black arts and mighty spells
and keeps them away from the house
and threshold of Bahram-Gushnasp, son of Ishtar-Nahid.
Amen, Amen, Selah."