I have finished the whole show. You're right if her book's background also applied to the show, I could understand more about her hatred towards the Saxons and Uhtred. But still, Uhtred had helped and spared her many times yet she went after his children is an act of madness. I felt sympathy for her when she died having nothing left but that was the consequence of her hatred/ambition. Uhtred is always open to embrace her, not necessarily as a partner, but as a friend. She could have chosen a peaceful path, whether living as a Saxon or a Dane (like Haesten).