Shiva Khan was only a preteen child when his overtly screwed up parents basically abandoned him into the streets of Kabul. He was predominantly Pashto with Hazara, Tajik, Punjab and Buryat Mongol admixture. Erse Nadru found him wearing just a loincloth and a singlet and took him into his care. Unfortunately, the latter was never just off the rails and catcalled him names, she basically verbally abused him out of spite and made him an unwilling young soldier.
As justified in the first part, he became something of a pretty callous sociopath hellbent onto nuking out the world. Once he lost the plot to the Shadow in a huge roast, he didn't regress into a childish state, but grew slowly but immensely in terms of character development, from plainly mild chaotic evil to smug lawful neutral tinted with the stock shonen rival trope.