Guzmán Guerrero Garcia was once a famous Mexican luchador known as El Cráneo, his theming based around skulls. He would play the role of a villain during his matches, and famous for his time, gaining many fans and merchandise.

Until he got tested for "enhancements" and was immediately disqualified from competition.

After that whole ordeal, he would shunned by his former fanbase, sponsors pulled out, and he was deemed a disgrace to the Lucha Libre tradition all together. Guzmán felt so much shame, he left Mexico entirely.

Years later, an up-and-coming supervillain, Purpetrator, found out about Guzmán and his story. Once he found him, he promised Guzmán a chance to become a real villain, and get back at the world. Guzmán would accept, donning his El Cráneo persona once again. Purpetrator would basically supply him with a serem made by Sai-Fai Labs to enhance his strength to superhuman levels, which he would have to take whenever he's called into action. (basically scientific super steroids This serem will totally not become addictive as his story progresses.