AntagonistsAntagonists are NPCs with goals opposed to the goals of the PCs.
I don't use the word villain or big bad because the PCs might befriend them first.
They may even work together on things.
They aren't evil just to be evil, they have a background and goals to accomplish.
Nim, Gnome Illusionist
Valna, Elven Druid
Vistra, Dwarven Wizard
Dara, Elf Vampire Cleric of Zehir
Zelenna, Night Hag
Tharaxus, Human Paladin