WARNING: The following contains major spoilers for director Rian Johnson's Star Wars: The Last Jedi. Seriously, MAJOR spoilers.
Over the past 40 years, generations of fans have grown up loving, and occasionally hating, the characters of the Star Wars franchise, many of whom have gained the status of pop-culture icons. However, filmmakers have seldom hesitated to kill off those legendary heroes and villains, from Obi-Wan Kenobi in A New Hope to Yoda and Darth Vader in Return of the Jedi and, far more recently, Han Solo in The Force Awakens. Rian Johnson's Star Wars: The Last Jedi continues that tradition, and increases the death count significantly.
The film is packed with twists and turns, and many of those are a result of heroic acts by protagonists, or villainous deeds by antagonists. If the loss of Han in The Force Awakens was a punch in the gut to fans, then at least one of the losses in The Last Jedi is going to take some time for them to process.
So, who dies in Star Wars: The Last Jedi?
Vice Admiral Amilyn Holdo
Played by Laura Dern, Vice Admiral Amilyn Holdo was a surprise character in that she didn't always seem as good as she appeared. Brought in to lead the Resistance after General Leia is injured in battle, Holdo almost immediately butts heads with Poe Dameron. She won't allow him to continue with his "act now, think later" approach to survival, and becomes an obstacle to Poe's goals.
It's plain to see, especially later in the film, that Holdo isn't attempting to play hero; she's simply doing what she thinks is in the best interest of the cause. Holdo is given an amazing exit from the franchise by deciding to take her vessel to light speed to ram and destroy Supreme Leader Snoke's flagship, Supremacy.
Best known for his debut in 1983's Star Wars: Return of the Jedi, from which his declaration of "It's a trap!" inspired countless memes, Admiral Ackbar returns in The Last Jedi to help the Resistance live to see another day. However, he unceremoniously perishes in the process, when his ship is damaged in an attack by First Order TIE Fighters.
It's a shame that such a classic character wasn't provided with a more heroic sendoff, but at least he died to save his fellow Resistance fighters. It's not as if he had a lot to do in the new trilogy, so his loss won't place the Resistance cause at a huge disadvantage.