Two Worlds, Two People

Demons and Humans lived amongst each other in peace, a simple portal separating the worlds but yet open to both species, The demon ruled being ruled by A human and A royal demon, Until one day, humans attacked, causing the still on-going war between the two worlds

What will happen four hundred years later, when a student within the hunter academy with a troublesome past meets a royal blooded demon whom is dealing with power and trust issues?