Edward always thought Leon was like him—a werelion, a human cursed to turn into a lion. While Edward's friend Kiyoshi had cursed him to level the playing field against Phillip, Leon never revealed the origin or reason for his supposed curse. Nevertheless, Edward's bond with Leon grew stronger with each encounter, whether they were fighting as beasts or chatting casually as humans.

After one fateful battle, Edward proved himself the stronger of the two, with Leon finally accepting defeat. Far from harboring ill will, Leon embraced this outcome. Having stood by Phillip's side since their first meeting, Leon now chose to align himself with Edward as a friend. Embracing this newfound brotherhood, Leon chose to open up to Edward.

To Edward's shock, Leon's human form—which Edward had come to recognize—wasn't real. It was merely an illusion. Leon wasn't a werelion at all; like Kiyoshi, he hailed from another realm where beastmen existed naturally. Sadly, it was a realm from which Leon had been exiled.

Throughout their encounters and shared experiences, Leon found a deep connection with Edward. He resolved to help his new brother in any way he could, be it spiritually or physically.