Over the course of 24 films (and three series), the MCU has killed off a lot of characters. While some films show only a few character deaths, others show many, sometimes more than the audience can handle. Many of the more recent deaths, such as Tony Stark or Natasha Romanoff, have been difficult for fans of the MCU.
However, enough time has passed where fans can pay homage to older dead characters without getting weepy. A lot of the early deaths are difficult to remember, but some of these characters have been crucial to the history of the MCU despite such brief appearances.
10 The Valkyrie (& Presumably Bor & The Asgardians Of His Generation)
The Valkyries of Asgard were a powerful female fighting force that was killed by Hela, except for Tessa Thompson's Valkyrie, of course. When Loki infiltrates her mind, fans are shown glimpses of the ancient battle where the Valkyries were slaughtered by Hela's Necroswords. It's unknown when this battle takes place, but it's implied that it happened hundreds if not thousands of years ago.
Additionally, fans have seen King Bor and his forces in flashbacks. While their deaths are never shown on screen, it's assumed they are gone, as Odin has taken his place. A statue of Bor had been erected in his honor until Thor decapitated it with a Dark Elf ship.
9 The Man Who Believed In Steve, Dr. Abraham Erskine (& All Of The Other People Heinz Kruger Kills)
Shortly after turning a scrawny Steve Rogers into the tall and muscular Captain America, Dr. Abraham Erskine is shot twice in the chest by a German spy by the name of Heinz Kruger. Erksine dies on the spot, and Kruger leaves a trail of bodies in his wake as he escapes with the last vial of the Super Soldier Serum.
After he shoots the old lady in the front shop, he uses her gun to kill the other undercover S.S.R. agents. Peggy then manages to headshot his driver from a significant distance, prompting Kruger to steal a cab and peel toward the docks with Cap not far behind him, on foot.
8 Heinz Kruger Himself (& Many Others During The War)
Just as it looks like Kruger is about to escape in his Hydra one-person submarine, Steve punches through the glass and pulls him out, tossing him onto the dock from the water. Steve then grabs him by the collar, demanding answers. Kruger responds by telling him that when he cuts off one head, two more shall take its place. He bites down on an arsenic capsule before saying, "Hail Hydra" and then dies with a foamy mouth.
Once Steve makes it out to the war, many soldiers are seen being shot by normal guns as well as Hydra weapons, presumably teleporting them to a faraway world. Many Hydra soldiers received the same treatment, but the Allies did win the war after all.
7 Dr. Wendy Lawson, AKA Mar-Vell
One fateful day when Dr. Lawson goes up in her jet with Carol Danvers, they are tailed by an unexpected extraterrestrial bogey. Despite Carol's superb flying abilities, the superior craft was too much for her to handle and they crash-land after taking some damage.
Lawson reveals herself to be an alien, specifically a Kree named Mar-Vell, and explains the purpose of the Light-Speed Engine to Carol before her untimely passing. Lawson is then shot by Yon-Rogg which kills her instantly. Carol then blows up the Light-Speed Engine, imbuing herself with powers and blanking her memory in the process.
6 Howard & Maria Stark
It's revealed during the events of Civil War that Howard and Maria Stark are murdered in cold blood by the Winter Soldier, aka a brainwashed Bucky Barnes. His mission was to retrieve the Super Soldier Serum Stark had in his trunk. While on a motorcycle, he hit their car with his metal arm, causing it to crash.
He then grabs Howard and punches him in the face repeatedly with his metal arm until he dies. He places Howard back in the driver's seat before choking Maria to death with his normal arm. It's a rather gruesome ordeal that Bucky will unfortunately never truly get to atone for due to Tony's recent passing.
5 At Least Two Of Talos' Skrull Buddies (& Many Others On Torfa)
Talos arrives on Earth with a task force of three other Skrulls, though Talos may have been the only one to survive the incursion. The first to die is the Skrull that impersonates Phil Coulson after Fury deliberately slams his vehicle into an oncoming bus. The second to die is Talos' science guy, Norex, when he impersonates Carol but doesn't know the answer to the question Yon-Rogg asks, prompting Yon-Rogg to shoot him.
The Skrull that disguises itself as a grandmother appears to have escaped. It's unknown where this Skrull is now, perhaps they will show up again in The Marvels or Secret Invasion. In addition to the thousands of Skrulls slaughtered by the Kree Empire, there are several Skrulls that are killed on Torfa when Yon-Rogg and his crew show up.
4 Most Of Yon-Rogg's Team & A Bunch Of Other Kree On Ronan's Ships
After Carol finally unlocks her full abilities, she is able to turn up the heat against Yon-Rogg, his team, and Ronan's ships. Some of Yon-Rogg's crew presumably die when Maria, Fury, Goose, and the Skrulls escape from Starforce and cause a massive explosion that pulls some wreckage into space.
Maria also outsmarts Minn-Erva and blows her to bits during a dogfight in a canyon. After grounding Yon-Rogg, Carol turns her attention to Ronan's forces. She plows through Ronan's ships as if they were tissue paper, presumably killing many on board. She also showcases the same durability and power during the final battle in Endgame.
3 Tony's Cave Buddy, Dr. Ho Yinsen (& Presumably Some Soldiers In The Fire Fight)
Tony re-meets Yinsen in a cave in Afghanistan after being kidnapped by the Ten Rings. It's assumed that many of the soldiers traveling with Tony before his kidnapping perished in the ambush, though some obviously escaped, including Rhodey. Yinsen saves Tony's life after a cluster of bomb shrapnel found its way into Stark's chest.
Yinsen then assists Tony with the creation of his Mark I Iron Man armor. While Tony was looking for a way to escape, Yinsen was always looking for a way to die. As morbid as it may seem, Yinsen wanted to see his family again in the afterlife. After Yinsen takes some fire, Tony stays with Yinsen until his final breath and then turns his attention to the soldiers of the Ten Rings base. Later on, after Tony perfects his Iron Man suit, he also makes quick work of several other Ten Rings members on an unsanctioned rescue mission.
2 Raza & His Faction Of The Ten Rings
Raza is responsible for the death of Yinsen, but karma quickly catches up with him as he doesn't last much longer himself. He manages to collect most of Tony's original suit and then attempts to bargain with Obadiah Stane. However, Raza clearly misunderstood his place in the hierarchy and is quickly paralyzed by Stane.
Stane tells him the paralysis will wear off shortly before delivering a brief villainous monologue. Obi's men outside then execute all of Raza's men after Stane leaves the tent. It's assumed Obi's death squad then went in and took care of Raza before hauling off the original Iron Man armor.
1 Obadiah Stane, AKA Iron Monger
Obi starts as an ally of Stark, but once it's revealed he was the one who orchestrated Tony's kidnapping, it's clear he's no friend. Obi nearly kills Tony when he removes the miniature arc reactor from his chest, but luckily, Pepper held on to the first model rather than junk it, as Tony had asked.
With some help from Rhodey, Tony gets suited up and heads to Stark Industries to stop Obi. After a brawl on the freeway, in the sky, and on the laboratory rooftop, Tony talks Pepper through overloading the full-sized reactor. The energy is too much for Obi to handle as he falls to his death, destroying the reactor in the process.