Malakho is an aged Dothraki in KhalDrogo's khalasar. After KoPono and KoJhaqo abandoned the khalasar following Drogo's incapacitation and death, Malakho remained. After Daenerys' hatched her three dragon eggs, Malakho pledged loyalty to the khaleesi.
Malakho can be seen in the background when Daenerys' silver horse dies of exhaustion in the Red Waste, and when the the Thirteen receive Daenerys at the gates of Qarth. Malakho attends the reception for Daenerys in the home of Xaro Xhoan Daxos. He and Kovarro have to be prevented from stealing Xaro's statuary. He guards Daenerys during her return from a meeting with the Spice King and is present when she discovers the theft of her dragons. He guards Daenerys's room after the theft.
After the duplicity of Xaro Xhoan Daxos is discovered, Malakho is the one who forces the would-be King of Qarth into his empty vault.
Malakho is a new character created for the TV series who does not appear in the A Song of Ice and Fire novels. It is mentioned that of the few Dothraki who stay with Daenerys after Drogo dies, most are old men or green boys.