Eska

"You amuse me. I will make you mine."

- Eska to Bolin

Eska is the daughter of Chief Unalaq and twin sister to Desna. Introduced as a potential love interest to Bolin, she quickly showed herself to be a sadistic and emotionally abusive girlfriend, who also enforces her father's malevolent agenda after Korra turns on him.

History
Eska first appears in the premiere of Book 2 alongside her equally emotionless brother Desna. Bolin takes a liking to her and attempts to woo her. However he quickly realizes that he has gotten more than he bargained for when Desna proves to be a controlling and emotionally abusive partner who delights in making her "lover" miserable. Eventually, Bolin can take no more, and Asami and Mako suggest that Bolin stand up for himself. Bolin tries and fails, prolonging his suffering. Eska ultimately decides that she desires to marry Bolin outright, at which point Bolin falls deeper into despair. Fortunately for him, he is able to escape from Eska when Team Avatar returns to Republic City, sending Eska into a rage. Blaming Avatar Korra, she vows to get vengeance on her for ruining her wedding and "stealing" her boyfriend.