Harry Riley was a pilot, and a good one. He loved his work, loved knowing that he was helping people get to where they needed to go... but he never learned to help himself.
Never asked for help or for a break, always took on everything he could and tried to fill the nagging hole in his heart with pride in his wings.
He ignored his own needs to the point where he wasn't sleeping, keeping himself going with coffee and caffeine pills - and when they failed him, when he dozed off at the controls during landing, it was only his copilot's quick thinking that kept them and their passengers from a fatal crash.
Harry lost his wings and walked into a bar, and into a bottle; he didn't plan to ever walk out. The Krampus had other plans.
He never used his words to ask for help, so they were taken, replaced with mechanical chirps and music-box birdsong; he let himself run down, so now, handless, he'll need the help of others to keep himself wound up at all. She ignored the pain in her soul, the missing piece she refused to acknowlege - and the Krampus knew just what to do about that.
Nowadays, Harmony can be found perched here or there around Toyland, wherever a bit of birdsong can help lift someone's burdens.
(Art, and Misfits in Toyland, by the wonderful @zal-cryptid !)