Black Jack, or Kuroo Hazama, is an unlicensed surgeon who can do anything if given the right tools- for a fee. He lives in a lone house on top of a cliff with Pinoko, his loyal companion, assistant and self-proclaimed wife who's three apples tall despite being eighteen years old.
They live comfortably alongside each other, having achieved an unique sort of balance over time. Pinoko takes care of most household chores, such as laundry, cleaning and cooking, whereas Black Jack focuses on his job. Pinoko is a moody, passionate girl. She is madly in love with her beloved doctor and makes sure to let him know by any means necessary. Her diligence with the daily chores is her usual way of showing her gratitude towards him. Black Jack, however, is a mystery. Although he appears, at first glance, to have his emotions in check, he tends to get overwhelmed when faced with situations he doesn't have complete control over. He is as compassionate as his assistant is, but doesn't show it nearly as much. Pinoko acts as a foil to Black Jack's sometimes gloomy, distant personality, being cheerful, affectionate and upbeat in most situations.
The Black Jack manga is relatively easy to find online, but I find every other piece of media relating to it excessively hard to access at times. Thankfully, Sheebzu did the hard work: