A servant is one whose function is to lend menial assistance to an employee or master. Servants who pressed into duty against their will are called slaves or indentured servants. Hired caretakers of a home are often referred to as butlers.
In DC Comics, billionaire playboy Bruce Wayne has his trusty family butler Alfred Pennyworth attending to his every need. Alfred is aware of Bruce's dual identity as Batman as well as the secret identity of Batman's various charges such as Robin, Nightwing and Batgirl. Alfred's duties range from preparing meals to stitching up Bruce's many injuries that he acquires during his superheroic explots.
In Marvel Comics, the Sorcerer Supreme known as Doctor Strange employs a man named Wong to serve a similar function. He refers to Wong as his trusty manservant, which is not the most flattering of job descriptors. Wong's duties include maintaining order in Doctor Strange's Sanctum Sanctorum, answering the doorbell, preparing meals and washing tough stains out of Strange's Cloak of Levitation.