She was manipulated by the first emperor that ee cannot argue.
Why she was manipulated, well because she was so blindly in love with him. After gaining all he needed from her he killed off her kind.
She wants to take revenge on his bloodline and the people of his country now even though they don't know anything. Which makes her a villain.
Her reason for revenge is sad but her solution for her sadness can't be accepted.
We can sympathize with her to an extend but not accept her solution.