I Hold the Heart of a Tyrant

The Crown Prince’s only friend, me, Euseniel Heartland. One day, our family was expelled from the capital for having had a bad influence on the Crown Prince. But after 14 years, we finally reunite, However, he has changed drastically. When asked why he changed, the Crown Prince answers that it is because he wanted to be the ideal man for me. But no, this is not the friend I used to know anymore, And it's not only his appearance what has changed, I'm sure there something else on the inside that's not the same as before. What could it be?