'Grey's Anatomy' season 18 introduces 1st nonbinary doctor in show's history

E.R. Fightmaster is making history on "Grey's Anatomy" as Dr. Kai Bartley.

The actor, who is nonbinary and plays the show's first nonbinary doctor, has been upped to a recurring character for the series' 18th season. Fightmaster was first introduced as Kai in the Oct. 7 episode.

Kai is a neuroscientist on the research team Dr. David Hamilton (Peter Gallagher) put together to find the cure to Parkinson's disease. Dr. Meredith Grey (Ellen Pompeo) and Dr. Amelia Shepherd (Caterina Scorsone) have joined the team, and will split their time between Minnesota and Grey Sloan Memorial Hospital.

"They are dedicated to their craft and extremely talented at what they do," reads ABC's character description for Kai. "Confident as hell and able to make even the most detailed and mundane science seem exciting and cool, Kai and Amelia bond over their shared love of medicine and the brain."

While Meredith was clearly familiar with Kai's work, it was Amelia who was enthusiastic getting to work with them. There was even a spark of chemistry between Amelia and Kai in the Oct. 14 episode.

Fightmaster, who got their start at Chicago's Second City Theatre, is best known for their role on Hulu's "Shrill." As a musician, they are half of the duo Twin.

They will next appear as Bartley when "Grey's Anatomy" returns on Nov. 11.