Miguel is an inmate and a Latin King.
Descriptions

Miguel was skinny, not fat, but he was short as a donkey was stubborn, and he got a wormy thang.
From Buck the Dumbass

His first cellmate was a Mexicano named Miguel. He was short and hairy and scrawny-built, with a big tangled mop of black hair that remained greasy no matter how often he washed it — and Buck done seed him warsh it buncha times. His sissel skin was just as dirty, and it was covered in crude tats. He was a Latin King in good standing, with the tattoos to prove it. Most them tats was rough and unsteady-done, cuz he got this shaky-hand Latin King named Sancho to do ’em.