the Avengers have beaten or repelled Kang, but it's not easy to defeat a man who sees the entirety of time as his playground.
Kang's mastery of time travel means that he has had several incarnations throughout history, each with their own, expanding history, the most famous being Pharaoh Rama-Tut and Immortus. However, they are considered completely different characters. The "main" Kang is Nathaniel Richards (possibly a descendant of the Fantastic Four's Reed Richards), born in the 30th century of Earth-6311, a technologically-advanced reality where humanity lives in absolute peace. Bored with the lack of stimuli of his age, Kang stole a time machine and, after some adventures in Ancient Egypt, ended up in the 40th century, a barbaric world devastated by conflict. Easily taking control of that era, Nathaniel created his new identity as Kang and used his advanced technology to forge a galactic empire.
Kang's First Battle With Avengers Shaped His Destiny
Growing bored once again, Kang decided to test himself with the "age of heroes" and conquer the 20th century. In his first attempt, Kang was barely defeated by the Avengers, but this gave him exactly what he was craving for, a challenge. The driving force behind Kang's every decision is a desire to test himself, to push his body and mind beyond the limits of humanity. The Avengers are his chosen foes, and Kang has challenged them to stop him many times.
Kang's biggest, most devastating attack, and perhaps his most crushing defeat, happened during the event Kang Dynasty, which ran in the pages of Avengers vol. 3 #41-54, written by Kurt Busiek and drawn by a team of artists that included Alan Davis and Kieron Dwyer. In this epic story, Kang unleashes the full might of his armies and technology against Earth, killing millions of people and putting the Avengers on the verge of defeat.
Kang Gets The Death He Always Wanted
Kang Dynasty had many memorable moments, such as Kang forcing the Avengers leader Wasp to sign the U.N.'s declaration of surrender, after his devastating attack against Washington D. C. However, due to the betrayal of his own son, Marcus (who fell in love with Carol Danvers), the Avengers are able to attack Kang's impressive Damocles Base directly, blowing it up and making it fall to Earth.
Kang survives, and emerges from the wreckage, wounded but unbroken, lifting up his sword and yelling a challenge to the Avengers: "Come and take me, if you can." Captain America steps up. The fight is brief and Kang is bested, but he reveals that this is what he wanted: an honorable death in battle after carving his name through time and space. Enraged by the death and devastation Kang brought, Cap takes him out with one final blow, sparing his life and denying him his wish.
Kang's Dynasty is The Best Kang Story, And His Greatest Defeat
In the end, Kang's greatest defeat happened not because of the betrayal of his son (which he was aware of), but because Kang himself was trying to put an end to his story, with what he considered an honorable defeat, entrusting his empire to Marcus. However, this desire was ultimately denied when Marcus came back to free his father from prison, forcing him to assume the mantle of the Conqueror again.
While in more recent comics Kang has become a more heroic figure who protects the timeline, he is at his best as a villain, and it will be interesting to see if the MCU movie Avengers: Kang Dynasty will adapt this epic story from the comics.