This page contains information regarding Star Trek: Picard, and thus may contain spoilers.
Zhaban was a 24th century Romulan male who worked as a housekeeper in the service of Jean-Luc Picard alongside Laris since the 2380s. He was a close confidant and advisor of Picard, and they held each other in high regard.
It was apparently through Zhaban that Picard negotiated his first interview with the Federation News Network since his retirement, having previously refused all requests. Zhaban reiterated three times that one of Picard's conditions for agreeing was that the interview would not address his resignation from Starfleet. However, during the live interview, Richter ignored this and did so anyway. (PIC: "Remembrance")
Zhaban was played by Jamie McShane, in his second Star Trek role. The character was named by Alex Kurtzman in tribute to writer, executive producer, and first season showrunner of Star Trek: Picard, Michael Chabon. 
He is one of the few Romulans to sport a beard.
While Laris more closely resembles Romulans of the Original Series era, who are physically indistinguishable from Vulcans, Zhaban possesses prominent brow ridges like the Romulans which appeared during The Next Generation era series and movies. Laris calls Zhaban and a Zhat Vash agent with similar ridges a "Northerner." (PIC: "The End is the Beginning")
Before his first on-screen appearance, Zhaban was featured in the Star Trek: Picard - Countdown prequel comic book, alongside Laris. According to the comic, before the supernova, he and Laris were agents of the Tal Shiar who fell in love, and then defected to aid Picard. In issue #3, a Tal Shiar commander addresses him as "Agent Noctis".