Battle of Heaven and Earth

"You turned your backs on Paradis in spite of being "island devils" to stand on the side of humanity to the end. You'd probably become the most respected beings in this world."

- Eren Yeager admits his foreknowledge of his defeat to Armin Arlert

The Battle of Heaven and Earth (天と地の戦い) was a final effort made by the Marleyan military, the Warriors, and former members of the Survey Corps against Eren Yeager in an attempt to bring an end to the Rumbling at Fort Salta. This resulted in the death of both Eren Yeager and the anomaly responsible for the Power of the Titans, ending of the Rumbling and eliminating the Power of the Titans from the world.

Prelude
Towards the end of the surprise attack from Marley on the island of Paradis, Zeke Yeager let out a scream that transformed many Eldians into Titans that quickly overwhelmed the surviving Marleyan soldiers. As Zeke went to reunite with his brother Eren, Warrior candidate Gabi Braun shot Eren in the neck and decapitated him; however, the Founding Titan that was residing within Eren saved him and due to Zeke making contact with Eren's head, both were sent to the realm where the spirit of Ymir Fritz resided. The two brothers tried persuading her to join them for their own means, but Ymir sided with Eren and caused the Wall Titans to break out of the three Walls on the island while simultaneously generating a new Titan body for Eren and imprisoning Zeke within the Paths.

Using the Founding Titan, Eren mentally sent a message to all surviving Eldians on Paradis declaring that the Rumbling will begin and all the enemies outside of Paradis will be destroyed. Soon, all the Wall Titans began marching off Paradis towards the continent of Marley. Survey Corps Commander Hange Zoë and Levi Ackerman encountered General Theo Magath and Pieck Finger, the holder of the Cart Titan and decided to form a truce for now to deal with the threat both sides had to face. Hange and Levi managed to find and recruit Mikasa Ackerman, Jean Kirstein, Armin Arlert and Connie Springer from the Survey Corps and Warriors Annie Leonhart and Reiner Braun, along with Falco Grice and Gabi to try and stop the Rumbling; Jean and Pieck would use subterfuge to also take Anti-Marleyan Volunteers Yelena and Onyankopon with them to help with the efforts. Arriving at the port where the Azumabito flying boat was located, the assembled group infiltrated the Yeagerists stationed there and were eventually discovered; Reiner and Annie used their Titans, and Pieck and Falco joined as support with the latter transforming into the Jaw Titan for the first time. After they secured the flying boat, Magath volunteered to stay behind and sacrificed himself to delay the Yeagerists from catching up with the ship they were using; unbeknownst to any of them, Yeagerist Floch Forster managed to anchor himself to their ship and followed them to their destination in Odiha. He fired several rounds into the ship's fuel canister but was swiftly killed by Mikasa.

As the group splits up, Hange volunteered to stay behind to fight the quickly approaching Wall Titans and equipped themselves with several Thunder Spears. They then appointed Armin as their successor and the newest Commander of the Survey Corps. Reiner and Pieck went with the group going on the flying boat, but Annie wished to stay behind; Reiner apologized for his prior actions against her and asked Annie to guard Falco and Gabi while they stay on the Azumabito ship bound towards Hizuru. The two teams left the harbor as Hange took out several Wall Titans before ultimately dying.

Early efforts
As the flying boat travels towards Fort Salta, Armin notes that due to obtaining the War Hammer Titan, Eren may not be residing within the nape of the Founding Titan and discusses with both the Warriors and Corps members about various means to incapacitate the Founding Titan. Suddenly, they are transported to the Paths and told by Eren that he will not stop the Rumbling and the only way they can stop him is to kill him; promising not to remove their free will, he transports his former allies back to the flying boat. The Survey Corps arm themselves with their vertical maneuvering equipment and explosives to detonate at the base of the Founding Titan's head.

While leaving on the Azumabito boat, Falco pleads with Annie that they can still help with the efforts to stop the Rumbling; due to injesting part of Zeke's spinal fluid, Falco recalls memories of a former Beast Titan that was capable of flight and is confidant he can do the same. After Kiyomi, Yelena and the crew abandon ship, Falco does indeed generate a avian form of the Jaw Titan and flies after the direction of the flying boat with both Annie and Gabi riding atop his back.

As both groups head towards a rendezvous, the Marleyan military has received numerous reports of the Wall Titans quickly overrunning the continent; as survivors and refugees begin to reach Fort Salta, war secretary Muller orders bombers to drop explosives on the quickly approaching Titans. Unfortunately, the Founding Titan summons Zeke's Beast Titan form and shoots down the airships with projectiles and eliminates all of them, rendering the fort defenseless. The flying boat is struck by several projectiles and destroys the left wing; Armin orders the Beast Titan to be a top priority target and as Onyankopon maneuvers the damaged shp directly over the Founding Titan, the soldiers jump and attach themselves to various spines protruding from the back of the Founding Titan; both Reiner and Pieck jump as well, transforming into the Armored and Cart Titans.

Battle on the Founding Titan
The group notices that Zeke's Beast Titan dissolved soon after Reiner defeated it, alerting them that Zeke was not inside it. As the others retreat so Armin can transform into the Colossus Titan, he is captured by another Beast Titan that was formed resembling an okapi. Many more Titans begin to spawn atop the Founding Titan's back, which react with hostility and drive the soldiers back. Pieck realizes that the Titans they are facing are resurrected versions of the Nine Titans from over the last two thousand years; the soldiers soon recognize several including Ymir, Bertolt and both Marcel and Porco Galliard. Pieck evades the Titans to reach Eren's nape but as she prepares to detonate the explosives, she is stabbed with several pikes made from former War Hammer Titans. Reiner is bested by Bertolt's ressurrected Colossus Titan and flung at the soldiers, knocking Connie unconscious and damaging Reiner and Jean's vertical maneuvering equipment. As they hang stranded underneath the Founding Titan, the soldiers are saved by the arrival of Falco's Jaw Titan and carried away before the other Titans can intercept it.