Arduano, Arnant, Harmaunce, Hermaunce
King of the Delectable Isle and the Red City.
Armant was slain by two treacherous protégés (Helain and an unnamed knight in the Prose Tristan; Passauver and an unnamed knight in La Tavola Ritonda; Helyus and Helake in Malory).
After his death, friends bore his body to the mainland, where they encountered Palamedes and convinced him to avenge their master’s death. Palamedes journeyed to Armant’s kingdom, killed the traitors, and gave the Red City to Marin, Armant’s brother.
Sources
Prose Tristan | 1230-1240
La Tavola Ritonda | 1325-1350
Le Morte Darthur | Sir Thomas Malory, 1469-1470