Who is Kyle Shin-woo before? And what happened to him before that made him a bad guy?

One wrong send that leads to one great love story. This is Blue Bear and Ms. Loner's story :) (started writing this story when I was in 3rd year high school. I'm sorry for errors and typos! Hello to my friends Bert, Rafael and Lette who inspired me to post this story here. Cheers!)