Most anime focus on the protagonist's development and life throughout the runtime. If a protagonist dies, it's usually at the end or somewhere toward the end of the anime. But then there are some anime that kill their protagonists off at the very start, usually to revive them in some way down the line.
Sometimes the protagonist gets a second chance, like Yu Yu Hakusho's Yusuke Urameshi. Sometimes the protagonist comes back to life like Dragon Ball Z's Goku. While there are many other examples of anime that pull this trick, including many isekai anime, this article will focus on 9 anime that begin with the protagonist dying.
Disclaimer: The following article will contain significant spoilers for the anime mentioned. Likewise, the opinions purely belong to the author.
9 anime where the protagonist dies in the beginning, like Yu Yu Hakusho
1) Yu Yu Hakusho
An older example, Yu Yu Hakusho begins with main protagonist Yusuke Urameshi sacrificing his life to save a kid from being hit by a car. This noble act from a delinquent gets him a second chance at life as a spirit detective, helping souls move on to the afterlife and battling demons.
Yu Yu Hakusho proves that death is not the end but a new beginning. At least, that's what happens to Yusuke. After his second round at life, Yusuke ends up forming a ragtag band of people to follow him to fight other demons threatening the world.
2) Dragon Ball Z
Set five years after the original Dragon Ball anime, Dragon Ball Z started with Goku dying to stop Raditz. Although Dragon Ball Z would later be known as an anime where death never truly sticks, the beginning of the Saiyan Saga saw Goku dying as Piccolo and him teamed up to save Gohan from Raditz.
While they did succeed, Raditz proved too strong for either man to face alone. It took Goku and Piccolo's strongest techniques and Gohan hitting him with a rage induced heatbutt to the chest, to kill him. After Goku's death, he'd have to run through Snake Way to find King Kai and get stronger. Gohan took over the role of deuteragonist in the anime from there on.
3) Konosuba
The first isekai example is Konosuba, wherein main protagonist Satou Kazuma got killed dying from shock after saving someone from being hit by a slow moving tractor. Kazuma was transported into a fantasy world by the rather arrogant Aqua, and then proceeded to become the greatest adventurer in the world of Axel.
The problem is, as the anime progresses, it becomes increasingly clear that all of Kazuma's traveling companions are all dysfunctional. From Kazuma himself being a sarcastic person, to Megumin's explosive temper and immaturity, to Aqua being shortsighted and everything about Darkness, this adventuring party somehow manages to survive despite all their problems.
4) Re:Zero
Re:Zero is an interesting look at the subject of death and rebirth. It involves protagonist Subaru Natsuki as he is summoned to a fantasy world and then is killed while trying to help a young half-eld named Emilia. He then revives a few hours in the past only to continue to die.
It turns out, when he dies he can carry on the memories of what happened before he revived. It's akin to being a living memory card and having a save file. It's not just Emilia that needs his help, as Subaru will come and go back in time every time he dies to continue helping people. It's an isekai with a time travel gimmick.
5) Jojo's Bizarre Adventure: Phantom Blood
Although an unorthodox example, JoJo's Bizarre Adventure's prologue Phantom Blood ends with Jonathan Joestar dying. While not at the very beginning, the end of the prologue has Jonathan dying when Dio comes back for his revenge after being reduced to a severed head. It also sets the precedent for other characters in JoJo's Bizarre Adventure's, as plenty of other protagonists have died in numerous ways.
For context, Dio got turned into a vampire and cut a swath through England in an attempt to conquer it. Jonathan gathered a gang of people and killed Dio's entire coven before confronting the man himself. Jonathan got killed by Dio, but Dio was trapped in the ocean for well over 100 years before Stardust Crusaders brought him back.
6) Zombie Land Saga
One way to start an anime is usually having the protagonist killed by a truck. Zombie Land Saga played this truck kill straight, as high school student Sakura Minamoto was killed by a truck on a morning she planned to submit an idol application. A decade later, she's revived as a zombie idol alongside six others from various eras of Japanese history to become an idol group to revive the failing business.
This colorful cast of characters includes a delinquient who led a biker gang, a former idol that that got killed after being struck by lightning, an aoiran during the meiji restoration, a transgender child actress who died of a heart attack, and an office worker who worked a double life as a demon slaying exorcist. Hilarious hyjinks ensue when they're all together.
7) That Time I Got Reincarnated as a Slime
Arguably one of the more famous isekai out there, That Time I Got Reincarnated as a Slime stars Rimuru Tempest. The famous slime turned god started off as an office worker who died saving a coworker from a stabbing. He was revived in a fantasy world as a basic slime monster.
Despite being a basic slime monster, Rimuru began his quest by feasting on grass used to make healing potions. This made him have a lot of HP and so he decided to start learning a lot of spells. Following this, Rimuru began learning higher and higher level spells until he became a god among the people.
8) Gantz
Two high school students, Kei Kurono and Masaru Kato, were both hit by a subway train after trying to save a drunk homeless man who fell on the tracks. Following their deaths, the two were teleported into a Tokyo apartment and shanghaied into the Gantz program. Their mission: kill aliens disguised as humans for the chance to return to their normal life.
The life or death stakes make it a different game. The participants are allowed to leave and do whatever they see fit until their next mission, provided they don't talk about Gantz or else their heads explode Suicide Squad style. The missions get tougher and tougher, even including an alien mothership, and the protagonists keep either dying or being revived in turn.
9) Excel Saga
In a much more comedic bent for this trope, the main character of the anime Excel Saga dies a lot and is always revived. Excel might be a bit of a hyperactive character who often loses people when she talks but, despite her incompetence, she always gives it 100% in her singleminded pursuit of Lord II Palazzo. The usual antics involve Excel being sent in to do something and dying a lot.
The anime always twists or demolishes cliches and conventions that most anime have, as the series is extremely random. Think of it like the pre-Pop Team Epic, just a fun and random series that delights in its own fun and hysteria. Where else but Excel Saga will anyone find two people and their dog causing havoc?
In conclusion, these have been 9 anime in which the protagonist dies at the beginning of the series. Whether to take it seriously like Yu Yu Hakusho did, or playing it for a comedy like Excel Saga, death for a protagonist is a key detail in these anime.