After marriage, Iris found out that this 'talentless' man was totally not how rumors stated him to be.
He was extremely cunning and shrewd!
He had his own plans to become the Emperor and planned to use this marriage to his advantage. He found out early on that Iris herself was a talented person, just naive. So he decided to manupilate her to help him in his cause.
Iris readily fell into his honey trap, believing his sweet words and devoting herself to him. She endlessly helped him, from doing the underhanded work to setting up officials and princes to clear the road for his ascension. She managed to raise him to the throne and once he became Emperor, Iris became the Empress.
Just when she thought that she could live her life happily, a great deal of agony struck her.
Suddenly, Leon changed. He treated her coldy, miserably and threw her away to the Cold Palace for petty reasons.
When she asked him why, he told her that he planned to make her sister, Aria the Empress.
Turned out he and Aria had always worked together. They had horribly used her and after that, discarded her!
They pinned a crime on her head, a crime she never committed, and passed on a death sentence to her!
That was when Iris found out that Leon and Aria hadn't changed. They were always this way to begin with!
Her whole life was lived as a puppet.
And that was when she swore.
Swore vengeance upon these scumbags!
Swore to make their life a living hell!
Only then would she be at peace...