Ghek is one of the main characters from The Chessmen of Mars.
When Tara became lost in the land of Bantoom, she encounted the strange people known as Kaldanes - a people with the physical appearance of a spider that ride on headless, humanoid symbiotes known as Rykors. Ghek is one of these Kaldanes.
Ghek originally served as third foreman in the fields of Luud. He was the one who captured Tara and had to watch over her while she was their prisoner. Like all Kaldanes, he appeared to be emotionless and talked with a monotone voice. All that changed when he heard Tara sing. Her singing gave Ghek something no Kaldane had experienced for many generations; emotions. Ghek believed it to be beautiful. The other Kaldanes did not understand his love for the music. For showing emotions, Ghek was deemed defective and sentenced to death. He agreed with this at first (showing he has not completely forgotten the philosophy of the Kaldanes), but changed his mind when Gahan showed up in Bantoom on a mission to rescue Tara. Knowing he had no future with his own species, Ghek helped him free Tara and Gahan from Luud and escaped along with the two, killing Luud and stealing the king's personal Rykor in the proces.
The three fugitives then ended up in Manator, where they were all imprisoned. Because his head and body are in fact two different creatures, Ghek could roam around freely using Ulsio tunnels while his Rykor stayed behind in the cell. Ghek used this to drive his guard insane and explore Manator, providing Gahan with crucial information. During a mock trial in which the three captives were to be sentenced to death, Ghek saved his new friend by temporarily stunning O-Tar with his psychic powers. Afterwards he delivered a message from Gahan to Floran.
Ghek then disappears from the narrative until the very end, when John Carter reveals Ghek and his Rykor now live in Helium. By this time Ghek has discovered the finer things in life and given up on the philosophy of the Kaldanes. He is not seen again in any future novels.