Ubayid (pronounced oo-BAI-yeed) is a Chammuran employed by Lady Zenadia doa Attaneh. He is the lady's armsmaster and is a skilled swordsman. It is implied by the mutabir that the rumors of murder in Lady Zenadia's house existed even before she took up with the Vipers. Before and during 1039 KF, he and the Mute commit a series of murders in Zenadia's name, including those of the spies that the mutabir has placed in the lady's house.
In 1039 KF when Lady Zenadia decides to sponsor the street gang called the Vipers, Ubayid provides gang members with new weapons. When Zenadia orders the deaths of Orlana and Sajiv, he knows of them and helps to turn the bodies into fertilizer. When Briar Moss storms the house looking for his student, Ubayid underestimates him at first, but then sees what Briar's magic did to his accomplice, the Mute - with thorns tearing him apart. Ubayid runs, presumably right into the hands of the Watch.
He only appears in Street Magic, where he is a minor character.