Despite dozens of heroes from across time and space venturing in and out of the TARDIS doors, not a lot of Doctor Who’s companions have actually left via the grim exit of death itself.
You might cast your mind back to someone like Adric, but the first companion kill goes back much further...and is about to come back to haunt not just one Time Lord, but two.
Yes, well before Adric was a twinkling silent-credits-over-that-maths-badge in someone’s eye, the dubious honour of the first companion to get killed off in Doctor Who history fell to the First Doctor-era character Katarina, a handmaiden from 1200 BC Troy.
And while there’s debate about whether she’s really a true companion—because this is literally what Doctor Who fandom is all about, the debates will last as long as time itself—considering her death came just five episodes after she joined team TARDIS in “The Myth Makers,” Katarina is widely considered the first major companion causality on the show.
She perished during the very next (and epic-length) serial after her introduction, “The Daleks’ Master Plan,” when she sacrificed herself in a hostage situation by blowing both herself and her captor out of an airlock in front of the Doctor.
Her role in the rest of the story was given over to another killed-off-quasi-companion, Sarah Kingdom, who allied with the Doctor but ultimately perished at the end of “Master Plan.” Seriously, they had the time back in the day.