Why Every Modern Companion Left Doctor Who
6. Tosin Cole - Ryan Sinclair
Although it was Mandip Gill's Yaz who would become the definitive Thirteenth Doctor companion, Ryan Sinclair was set up as the focus of Doctor Who's eleventh series. Played by Tosin Cole, Ryan appeared in 20 episodes, two seasons and two New Year's specials, bowing out in 2021's Revolution of the Daleks.
Cole never gave a definitive reason for his departure, but immediately following the show with a lead role in crime miniseries 61st Street and a small role in arthouse movie The Souvenir Part II suggests he was keen to pursue other acting roles. It's also possible that he was just a bit knackered from the relentless pace of making a show like Doctor Who.
As he prepared to leave Doctor Who, Cole told the press that it had "been an honour to work on such a cultural institution with fans across the world" but that he was "looking forward to having a rest though!”
Unlike his on-screen grandad, Cole never returned for Power of the Doctor, but he remains busy, leading Netflix's smash-hit superhero series Supacell.