Mordo has a very interesting backstory, one that requires that emotional vulnerability I have written of. Baron Karl Mordo was born to Nicolei Mordo, Viscount/Baron in Romania. Mordo's father has aspirations of grandeur and magic and "sold" young Karl Mordo, his son, to his Uncle. His Uncle used Mordo is dark arts ceremonies, eventually readying the boy for a sacrifice. Mordo's entire backstory is one of betrayal, abuse and dysfunction, so he is not a classic "villain" in that his motivation comes from desiring acceptance, almost from a father figure. He has a proclivity to bad deeds to power grab, akin to a concentration camp surviver hoarding food, never knowing when the next morsel will come along (in this case, Mordo's need for power). Mordo's relationship with The Ancient One is strained, as Mordo grows his skills and gets jealous of any attention paid to other students, i.e. Strange, by The Ancient One. Because Mordo has so many levels and such a fantastic backstory, the casting requires someone like Javier Bardem who not only has the looks, but the needed skills to give the subtext and layers to the character (just look at his work in Skyfall. Silva was evil, but Bardem successfully brought the emotional gravitas to make Silva three-dimensional; not an easy feat for an archtype Bond villain).