I visited our past

Killian was indeed a little shocked to hear his backstory. For as long as he could remember, he had lived in a grand palace that felt like his only home. As a child, he believed the king and queen were his real parents. He did everything he could to earn their affection, but there was always a distance between them.

No matter how hard he tried, they never showed him the same love they offered to Cassius, their biological son. Back then, he didn't understand why their love felt so different, but as the devil came into existence in his mind, he understood one painful truth. 

The king and queen had never loved him because he wasn't their blood. He wasn't their child. When he realized this, he felt a deep ache, but he chose to accept it. He didn't search for his real parents; it seemed pointless since they were absent from his life. Most importantly, he decided to embrace his fate.