This is Sleet the IceWing SeaWing hybrid. Sleet's mother- Urchin was in love with an IceWing, but she didn't want anyone to know about them, so she left the Kingdom of the Sea just as she discovered she was with egg. Urchin went to the Ice Kingdom with her unhatched egg, but she didn't know about the Great Ice Cliff, so she was killed when she went across- but her egg wasn't. Because it was half IceWing, the egg survived, buried in snow. Months later, a hermit-of-an-IceWing found the egg. He collected interesting things so he kept the egg, not knowing it was alive. But Sleet hatched, and Frost raised him as a son.
And no, the father didn't know he had a child.
Hope you like him!