Clara Sullivan is a former witch who was part of Ruth Winterbourne's coven. When Ruth discovered that she was using her magic to kill people [especially men] she came to her house and took away her magic by breaking her talisman. Clara became enraged and tracked down Aleister to help her get revenge. She was tasked with killing Aleister when he was an infant but couldn't so she left him on the porch of a church that took him in and helped him find a family who adopted him. She is ultimately killed by Savannah Levine who uses her powers to choke her to death in the season two finale [episode ten] "Fine Temporum".