The relationship between two ancient witches, Silas and Qetsiyah.
They are first seen interacting during Original Sin. Qetsiyah, also known as Tessa, held a grudge against him and his lover, Amara, for two thousand years for betraying her. Tess loved Silas unconditionally and even created an immortality elixir so that they could live forever together. However, Silas stole the elixir on their wedding day and gave it to Amara instead and himself, betraying Tessa. Her whole purpose of creating the Other Side was to punish him for cheating on and leaving Tessa for her, for eternity. She never forgave him for breaking her heart.