Mazikeen is Lucifer's assistant, she is a demon and daughter of Lillith making her one of the Lillim.
Physically Mazikeen appears like a normal human woman with long dark hair and fair skin, but as she is of the Lilim her form can change as she sees fit. What marks her out as a demon however is the left side of her face that appears to have simply rotted away, exposing teeth, brain, bone and missing an eye.
After Lucifer abdicated Hell in order to get back at Dream of the Endless, Mazikeen remained as one of the last demons refusing to leave Lucifer's side before he forced her to, after allowing her to accompany him. The pair settle in Los Angeles where they open a piano bar called Lux where she primarily function as head waitress. Shehas to disguise her features behind a white half-mask and a piece of cloth wrapped up in the manner of a hijab.
Their time in Lux is not left uninterrupted and several members of both Heaven and Hell visit the bar, setting off Lucifers long quest to escape predestination. While Luficer is attempting to regain his lost wings, a pair of Jin En Mok of the Shapeless come seeking the portal Lucifer left open into a new Creation. Mazikeen manages to kill one of the Jin En Mok by eating his heart, but she is mindcontrolled by the other. One of the other staff, a waitress called Beatrice, try to help by dousing them both in strong alcohol before threatening to set them alight, not knowing the otherworldly origins of the two. The Jin En Mok controls Makizeen's flesh to the degree that she dies in the fire.
After the fire is spent Makizeen is found by Jill Preston, recently empowered by a living deck of Tarot cards drawn by an angel. Jill heals Makizeen to full health, but not understanding the particular aesthetic qualities favored by demons, she restores both halves of Makizeen's face. Makizeen considers herself mutilated and swears revenge on Jill, to Lucifers mild amusement, before she leaves Lux in order to find a way to restore herself.
At the end of the series, Lucifer abandons Gods Creation entirely, leaving everything from it behind, including Makizeen, who is at the end dissuaded from killing Jill.