Darach was a very evil and ugly monster in season 3a. She makes her appearance as a new teacher at Beacon Hills and went by Jennifer Blake.
the audience learns her actual name is Julia Baccari and that she was the Druid emissary for Kali's pack. Kali and Julia had a great relationship, but when Deucalion had multiple Alphas kill their own packs, he also had them kill their emissary. Kali wounded her and left her for dead, but she ended up surviving. Darach is trying to gather enough energy and power to defeat the Alpha pack for what they did to her.
