The culture was unique, the people friendly. Icarus was always treated well being the son to a "noble." Family was very important to Icarus, however his mother had died giving birth. Or so he was told. His father always resented talking about he. Icarus felt guilty somehow for her death, it was his fault. He blamed himself for his fathers grieving.
Those feelings festered into a sensitivity he was unable to deny, the simplest of words hurt. However it was best to smile through the pain. He often wandered between the realms, thinking it odd that he was so sensitive.
A lot of the other Twili didn't seem that way, were they hiding behind smiles too? Or was his father holding secrets back. The likelihood that he would ever find out was so minimal.
Icarus was very quiet, so in tuned to himself that he tuned the world out. He fought when necessary but would rather talk it out, his father was proud to say he fit right into the "nobility."
He never went out into the light realm much because he often found himself in animal form, simply out of comfort. It upset him that people ran away when he approached, or tried to attack him.. but a beast is a beast.