Bruno was unhappy living in Neovia, with his advances on Lily being rejected. But Krawley's offer of a magical potion made him strong and athletic - at a price. He mutated into a horrible creature, and when the rest of the town joined him, he was chased out of the town. He lived in a cave for years, before being reunited with his sister, Sophie, and helping her save Neovia. He has since returned home. Before becoming cursed, he looked like this:
Sophie! What do you think you're doing?!
I... uh... Help! There's an angry mob after meeeee! *flees into the Haunted Woods*