Massive spoiler alert warning!
Game of Thrones fans fully expected to say goodbye to some of their favorite characters in Episode 3, "The Long Night." And of course they were right to do so—there was no way the entire cast would go unscathed when the Night King's army (hundreds of thousands of the undead) as well as undead Viserion were marching straight toward the Winterfell castle. The odds were fully stacked against them, and most of the episode was a grim blood-bath. Below is the full, confirmed list of main characters who were killed.
1. The entire Dothraki army
Melisandre lights the Dothraki army's swords on fire, and they are the first ones to go marching into battle. The light from their swords go out completely, and they all perish. The moment is totally unreal.
2. Edd Tollett, leader of the Night's Watch
Edd Tollett dies saving Sam Tarly.
3. Lyanna Mormont
Lyanna is first slapped by an undead giant, and it's unclear whether she survives that. Moments later, she gets up and charges at the giant, who plucks her from the ground and squeezes her so hard, we hear her bones break. Before she dies, she stabs him in the eye and kills him, like the badass she always was.
4. Beric Dondarrion
Beric dies protecting Arya—and we later understand why he was brought back from the dead so many times to do so (more on this later on). He is stabbed to death by the wights.
5. Theon Greyjoy
Theon fully redeemed himself when he was the last one keeping Bran alive. Alas, he's speared by the Night King.
6. Jorah Mormont
Jorah dies protecting Dany, which, to be fair, is the only way Jorah would ever want to die. He's stabbed to death by the undead.
The Red Witch chooses to end her (never-ending) life by taking her choker off, and walking into the snow. She's done everything that she was put on earth to do, after all. She transforms into her true, ancient self, and collapses.
8. The Night King
Okay, back to Arya. Beric's purpose for being alive was to keep Arya alive this entire time. Arya was most likely destined to kill the Night King, which she did, by stabbing him.
Viserion is finally put to rest once Arya destroys the Night King. He shatters into a billion pieces of glass. RIP.
10. How many dragons are left?
Definitely one, but probably two. *Phewf*. As of right now, we've only seen Drogon. We thought we lost Drogon when he was overtaken by a huge hoard of wights, but he thankfully made it out alive in time to comfort Dany, who cries over the death of Jorah. Rhaegal's fate is a bit less clear. The last we saw him was when he took on Viserion, and was at least badly maimed. Poor Rhaegal came crashing down to earth, so he might be dead...but chances are he's alive, but severely injured. Because otherwise Rhaegal would have been one of the undead the Night King resurrected, and we definitely didn't see a second evil ice dragon.