Fan Casting Mi Go in Hollow Terra

Mi Go nothing's known about him nor his's origins other than the fact that he's in the hollow earth and is sort of a rather strange yet interesting missing link to man and creatures like apes and sasquatches dubbed the Homo Wellis who are theorized to be descended from the Gigantopithecus who have somewhat human like intelligence like gorillas, dolphins or crows but instead of talking communicates via growling, hisses, grunts and sign language