7) River Song
River Song seems to be the most “Marmite” character ever to appear in Doctor Who. While some fans never warmed up to her due to how radical she was, others love her for the same reasons.
Whatever your opinion, you have to admit that River is one of the most high-concept creations you’ll find in the show. A bit like a cross between Lara Croft and The Time Traveller’s Wife, Professor River Song is a gun-toting, time-travelling archaeologist who it later turns out is – spoilers, sweeties – the Doctor’s wife. Tragically, the pair keep meeting in the wrong order. The first time the Doctor met River, for example, was the day that she died.
As the only woman to manage to tie the Time Lord down (well, that we know of), Professor Song is undoubtedly one of the strongest female characters the show has given us. She’s been such a major part of Steven Moffat’s time on the series, in fact, that she’s encountered David Tennant, Matt Smith and Peter Capaldi’s Doctors.