The Time Lord's companions are important in "Doctor Who" season 10, and so the grand entrance of Clara's replacement will mark an enormous change for the long-running sci-fi series, at least in terms of the tone.
Showrunner Steven Moffat is already on the lookout for a new sidekick for "Doctor Who" season 10 to fill in the void left by Clara's essayer Jenna Coleman.
He is currently in the early stages of casting, and during an interview with Digital Spy, he explained how crucial and difficult this task actually is.
"Because the tone of the show is so driven by what we call the companion, it's so driven by that. It's not just casting a supporting character. It's not. It's the lead or the co-lead, and it will become their story. So, it's a huge, massive thing," Moffat stated.
Moffat is hard at work putting together "Doctor Who" season 10 and some might think that he is putting a bit too much effort because the upcoming season will be his last and he wants to end his stint in the series on a high note.
In the same interview, the hit show's executive producer has expressed his plan to leave the series. However, he refused to elaborate and said that really has "no idea until I'm there." But he did admit that the emotional aspect of leaving is just too great to handle.
"Everything is difficult in Doctor Who, including leaving, and I would never do anything to harm it. I would never leave it in the lurch because it means too much to me," Moffat told Radio Times. Until, he gets the urge to "do something else," he will be around.
That being said, "Doctor Who" season 10 may or may not be Moffat's last. Speaking of which, series lead star Peter Capaldi has also broached on the possibility that the upcoming season may also be the final time he will suit up as the beloved Twelfth Doctor.
