Joaquin wasn't initially the crown prince. He wasn't named the crown prince being the second son of the emperor. The firstborn was said to be a bright, wise, and remarkable young man whose future was secured with the emperor and the late empress backing him up.
Unfortunately, the young crown prince, although birthed for greatness, wasn't blessed with a long life. At the age of a fleeting fifteen years old, he passed.
Traditionally, the title of the crown prince was passed on to the current heir of the throne, Joaquin Imperial. No one opposed this decision, for one fact remained. Tradition aside, Joaquin wasn't less notable than his older brother. The only difference between the two young men was their differing hearts and beliefs.