I decided to take a different spin on this - but I'm not quite sure where it came from xx
Slavery had sometimes been present in Underland - by other names and by necessity, but present.
As a child he'd been sold to the King and Queen as the youngest of twelve, his parents unable to support their family. They had all needed the money.
When they were children he'd played with Iracebeth, Mirana and the other castle children. He'd been closest to Iracebeth as they were closest in age even if they hadn't always gotten on. She'd liked to hit him with her dolls. The only toy he'd ever been consistently allowed to use was the knight and horse. Eventually she got bored with her King and Queen dolls and took the Knight off him.
He never really forgave her for that.