Avengers: Endgame changed the face of the Marvel Cinematic Universe permanently. Besides the horrors that stemmed from the blip, Tony Stark and Steve Rogers have died. With Sam Wilson effectively taking over as Captain America and Jane Foster teased to take over for Thor in Thor: Love and Thunder, it's safe to say the Avengers are heading in a drastically different direction. Kang the Conqueror is expected to be the main villain of phase 5 which sets up the MCU perfectly for a live-action adaptation of "Kang War."
"Kang War" by Mark Waid and Mike Del Mundo took place directly after "Civil War II" in the first six issues of 2017's The Avengers. This storyline saw Vision travel into the future and abduct baby Kang, thinking that this would bring an end to the villain. Instead, it created further paradoxes that allowed Kang and his variants to travel through time together. This led Kang Prime and the Scarlet Centurian to murder each of the Avengers in their cribs in hopes of erasing them from all of existence.
The heroes were saved and pulled into limbo by a future variant of Kang. Hercules was the only active Avenger left alive since Kang could not locate his infant version. After being gifted an amulet from Sibylla the Oracle that protected him from Kang's time meddling, he traveled to Vietnam in search of the infant. The Oracle's amulet allowed the rest of the Avengers to return from Limbo. They fought back Kang and his variants before the infant was given to Nadia Pym to return to the correct time. Nadia would return the infant Kang and save the infant Avengers from their own time paradox as well. They then turned their attention on Kang.
With the help of a future version of Vision, the Avengers traveled through time and recruited their greatest members. This included Stan Lee's original Avengers as well as Steve Rogers, Namor, the Black Knight, Captain Marvel and She-Hulk. They then split up into three teams and attacked the sources of Kang's power. Their attacks proved successful and they soon joined back up to apprehend a depowered version of Kang at his base.
Before they could capture the powerless Kang, other variants of Kang including the Scarlet Centurian, Immortus and Doctor Doom all appeared to protect the powerless variant. Luckily, Hank Pym had reworked one of Kang's devices to give him the power to steal others' futures. He used this against the Kang variants trapped within Giant Man's device who were then entrusted to entrusted to watch over Vision's future.
"Kang War" has the perfect plot for the MCU's phase 5 considering the events that have recently taken place. Sam Wilson, Jane Foster, Peter Parker, the daughter of Hank Pym, and Vision are all members of the current Avengers roster. In addition, the gathering of previous Avengers leaves an opportunity to bring back fan favorites like Iron Man or even new faces like the Black Knight.
Not only do the heroes match up, but it also provides an epic and compelling story about Kang. It properly demonstrates the ultimate power that Kang wields while showing his influence on history. Many fans wondered why the Avengers did not simply go back and kill Thanos as a baby in Avengers: Endgame. This story follows up on that idea, but with a villain that can combat it. Kang's retaliation by murdering baby versions of the Avengers and erasing them from existence is an even darker version of the blip.
With a storied history like the one Kang possesses, there's no telling where Marvel will pull from to tell his story in the MCU. While a proper introduction needs the assistance of the Fantastic Four, this story could introduce Kang without needing anyone but the Avengers. Not only does it use Avengers that were previously introduced in earlier phases, but it could also bring in She-Hulk and the Black Knight who will be extremely fresh to the MCU and ready for more time at the forefront. Regardless of who attempts to stop him, Kang is bound to rival Thanos' destruction when he enters the MCU.