Cha-Cha

Cha-Cha is a hitwoman who travels through time to erase her targets, and she treats the job like any other trade: efficient, humorless, allergic to complications. Paired with the more sentimental Hazel, she wants the mission finished cleanly and can't understand why he keeps wanting to slow down and feel things.

Mary J. Blige plays her with a flat, unblinking menace that never tips into cartoon villainy — she's funniest and scariest in the same deadpan register. The show pairs her cold professionalism against Hazel's midlife wistfulness, and Blige's stillness makes every outburst of violence land harder.