Red was born with little power in his life, weak limbs, orphaned and bullied for his differences. His only semblance of happiness was from his childhood friend, Faron. However, after she left to pursue interests within other regions of Hyrule, Red was left on his own again with his weakness.
Hence he pursued Alchemy, and learned of a forbidden recipe containing Lynel blood that would transform him into a Lynel for a limited time. The power was intoxicating, and ignited Red's passion for alchemy. However, upon the city officials finding out that he used forbidden magic, he was kicked out of Akalla City. With his isolation, he went to live within an old hunting cabin, refurbishing it for his own purposes.
With a new desire in life, to live as a powerful creature, Red continued working with alchemy to see if he could change this forbidden recipe, and make it more efficient. He'd spend his days, hunting as a Lynel, with his powerful weapons, and nights, tinkering at the formulas.