Heartless Phoenix Queen

She was the number one killer of an organization in the twenty-first century,
to be shot by a fellow traitor,
The soul passing through to the Bei Yue Kingdom,
Become the daughter of the marquis.
And he was a deep and wise young monarch,
The plan was executed step by step, and the only thing they wanted to do was call Ba Tian their next target.
When the merciless killer meets the cold-hearted emperor,
When killers and emperors work together to create a hegemony,
What would the result be?