Tell me about their favorite memory. The memory can be from any point in their life ranging from childhood to the present
Oh I love this! Ok so-
Destrian: The first time he used his power in battle and won. His power is inherently fighting-based, so when he had the chance to use it successfully while fighting, he was ecstatic.
Sadon: Probably when he and Destrian met a creature called a vaegseer, which are rare and ancient creatures that are said to bring good luck.
Aryn: The time their brother took them into the market and bought them a new book for their birthday.
Peter: The Ta'masha la Taa, or Festival of Lanterns. He just really likes dancing and flowers and the Festival has both.
Oh, dear… I realized my protagonist doesn't have "favorite memories", he has unproductive habits or even addictions that give him a momentary sense of relief. They're not "favorite" except by default because "life is Pain except maybe for this sometimes".
The least destructive of these habits is sitting on the fence of a country manor and watching the horses wander around the grassy field beyond the fence, and one time a horse got very nearby the fence and let him pet its snuffly soft nose. The rest of his life is pain. Pain and misery.