Ghron is a secondary antagonist in the story A Fighting Man of Mars. He is one of the cruelest and maddest beings known upon barsoom, the jed of the city Ghasta, sometimes known as the spider of Ghasta. He is a terribly ugly example of a Red Martian, one of his more peculiar traits is that he has hair on many places on his body (red martians lack body hair). He is cruel to the subjects of his city, the pits below his palace contain many rooms for torture. He surroundings reflect his madness, murals depicting ugly half spiders adorn his palace, his meals are entertained by the dancing of those deformed in the torture chambers beneath his palace.
Tan Hadron and Nur An encounter this madman when they end up in the Valley Hohr and Ghasta after having been sentenced to "The Death" in Tjanath. They are taken captive by him and given a choice: work for him (and thus become torturers themselves) or be tortured. They manage to escape his palace however.
After Tan Hadron and Nur An escape, Ghron is never seen or mentioned again in the rest of the book nor any other Barsoom novel, so it's unknown if his cruel reign was eventually put to an end.