Melchiresa is an archdemon mentioned in several of the fragments of the Dead Sea Scrolls.
One of the Dead Sea Scrolls (4Q535, Manuscript B), which dates to the second century BCE, is written from Amram's point of view, and hence has been dubbed the Testament of Amram. The document is dated to the 2nd century BC and, in the form of a vision, briefly discusses dualism and mention three evil spirits: Belial, the Prince of Darkness and Melchiresa.
I saw Watchers in my vision, the dream-vision. Two men were fighting over me ... holding a great contest over me. I asked them, 'Who are you, that you are thus empowered over me?' They answered, 'We have been empowered and rule over all mankind.' They said to me, 'Which of us do you choose to rule you?' I raised my eyes and looked. One of them was terrifying in his appearance, like a serpent, his cloak, many-colored yet very dark. ... And I looked again, and in his appearance, his visage like a viper. ... I replied to him, 'This Watcher, who is he?' He answered, 'This Watcher ... his three names are Belial and Prince of Darkness and King of Evil.' I said (to the other Watcher), 'My lord, what dominion (have you?)' He answered, 'You saw (the viper), and he is empowered over all Darkness, while I (am empowered over all Light.) ... My three names are Michael, Prince of Light and King of Righteousness.
Melchiresa also appears in 11QMelch in direct opposition to Melchizedek, the leader of the forces of good.
Fragment 4Q280 describes a series of curses laid upon Melchiresa:
Accur]sed are you, Melki-resha, in all the pla[ns of your guilty inclination. May God [make you] an object of dread at the hand of those exacting vengeance. May God not favour you when you call on him. [May he lift his angry face] upon you for a curse. May there be no peace for you in the mouth of those who intercede. [Be cursed,] without a remnant; and be damned, without salvation. - 4Q280