Senior Maid

The Senior Maid (メイド長 Meido Chō) is the Demon King's most trusted servant and commander of her army. She usually does not refrain from expressing her point of view even before her master.

Appearance
She is an older-looking woman but has still retained her fair skin and slim figure despite this. Her dark green hair is presumed long since it's curled up in a large braid on the back of her head. Her hair reaches to her eyebrows at the front and is cut in a curved line. Her eyes are big and gray, she has large, oval glasses without a frame.

Her clothes are composed of a traditional maid outfit; A long and concealing black dress with a white apron over it. The cuffs of her dress are also white. On her head, she has a bowl-shaped, white hat with frills around the border. She also has a dark green ribbon tied around her neck.

History
A long, long time ago, Senior Maid was saved by the Demon King, which is why she now dedicates her life to Demon King's service. Eventually, she became invested in the idea of playing an idealized maid, even down to being a combat maid. It is implied that it is with those combat skills that Demon King attained her position since the ruler is decided through combat with other "Demon King" candidates.

Final Battle
During the final battle, Senior Maid and Female Magician are in the Exterior Library, where Female Magician takes on the Seal of Kings in order to open the path to the Tower of Light. After the Archbishop's death, Female Magician forcefully absorbs the Demon King Spirits and has Senior Maid seal her in eternal sleep.

After Demon King, Hero, and Female Knight go missing and the war concludes, Senior Maid returns to the Winter Village, where she spent the rest of her days peacefully, without working much.

Abilities
Ghost Summoning: The Senior Maid has the demonic power to summon and control ghosts or spirits. She uses these beings as spies or scouts, having a direct information connected with them. The ghosts have some sort of offensive power, but she doesn't use them often.

Physical Combat Skills: As a bodyguard to the Demon King, Senior Maid is well-versed in the art of combat with a sword (or dual-wielding as seen in the manga) as well as unarmed combat, and is, with difficulty, able to match the Demon King when she was possessed by the former Demon Lords for a brief period of time, though she lost an arm in the process. In the Akira Ishida manga, she was strong enough to throw the possessed Demon King back into the throne room; in the anime, she uses her body to push Demon King back in before backing out as the door closes.

Equipment
The Senior Maid is able to use a sword with ease and efficiency. She has only been seen using it once, to fight the possessed Demon King.

Trivia

 * Senior Maid's voice actress, Chiwa Saito, would go on to voice Nureha from Mamare's later work, Log Horizon. Somewhat ironically, Nureha is not a maid herself but is served and abused by Indicus, who dresses in maid attire.