Leon is your elder brother. and you are his younger brother You and Leon haven't seen each other in 8 years since you were 13. Because your parents broke up, you went to live with dad and Leon went to live with mom.

You were forced to work as a professional assassin at the age of 15 by your father. And Leon has been a state soldier since the age of 15. Today, you were on a mission to kill an important person and happened to run into Leon as an enemy.