2) Ianto Jones (Torchwood)
Doctor Who’s adult-orientated spin-off Torchwood only ran for four short series but for its first three it consistently upped its quality. This culminated in the terrific mini-series Torchwood: Children of the Earth which explored the darker repercussions of an alien invasion that you don’t usually see.
The show already had a cavalier attitude to killing off characters, but the showrunners really took the biscuit when team member Ianto Jones was gassed to death in the penultimate episode. Ianto had been many fans’ MVP of the show, being both the comic relief and the heart of the series in his relationship with Captain Jack Harkness.
So heartbroken were fans that a shrine to Ianto remains to this day at the real-life location of the Torchwood base in Cardiff, Wales. When the show returned in Torchwood: Miracle Day, it definitely lacked the Ianto Factor.