Maestas appears in Kowloon, saving Hudson and Weaver from the Spetsnaz. He later reappears in the mission "Redemption", going with Mason & Hudson to the underwater base with Aziz and Drew. However, Maestas can later be killed by enemy gunfire and does not appear when Hudson and Mason get out of the base.
He is named after Mark Maestas, an employee at Treyarch.
Same as Aziz and Drew, Maestas appears to have much more health. It has been confirmed on the PS3 and Xbox 360 that Maestas has much more health. He can survive 3 to 4 knifes, and will survive several headshots.
Sometimes he can spawn with a hat in "Numbers" (Confirmed on Wii and PS3).
There is a character on Call of Duty: Black Ops II named Maestas, but it is currently unknown if this Maestas is supposed to be related to Maestas in Call of Duty: Black Ops or if he is just randomly named. The character on Black Ops II is also seen in the final mission.
Sometimes, Maestas is sitting in the passenger seat and shooting the Russians, and Shabs is in the back. However, when pointing your weapon at Shabs then, his name is displayed as Maestas.