Adam’s clone ‘sister’. She is the second. The first, Lilly, was killed in an attack by Danello in the Bazaar when Adam and her were only children.
Adam and Clayton struck a bargain to create Evellyn in exchange for some random(specific) acts of kindness(murder). Adam had the opportunity to carry out of one these acts in Giza before Clayton’s organization was undone by Nod’s presence.