Elena "Red-Eyed Dark Elf"
About
While the Black Dragon Karas took the spotlight as the major threat among the people, Elena herself was in fact the main antagonist working in the shadows to secure the Black Dragon Jewel, being absent most of the time.
Near the end of the movie it is revealed that Elena is the reason for the war between humans and elves as she manipulated and betrayed both factions, reason for what she was exiled from Anu Arendel.