WARNING: The following contains spoilers for Attack on Titan Season 4, Episode 23, "Sunset," now streaming on Funimation, Hulu and Crunchyroll.
In a reveal that perhaps most Attack on Titan fans saw coming, Levi Ackermann is indeed still alive. The fate of humanity's greatest soldier was left vague in the premiere episode of the Final Season: Part Two when Hange Zoë dove into the river with Levi's body. A lot has gone down since Levi was last conscious -- although it looks like he still isn't -- and mangled body or not, the Rumbling is an all-hands on deck situation. Missing some fingers and an eye, Levi is probably going to want to find a way to contribute when he learns what Eren has done and what has become of Paradis Island.
In the finale of the Final Season: Part One, Zeke Jaeger detonated a Thunder Spear at close range in a desperate attempt to escape Levi's clutches and continue his plan with Eren. When AoT returned for the Final Season: Part Two, Hange, who was being held prisoner by Floch and the Jaegerists, stumbled across Levi's seemingly lifeless body. Though Floch found it fortunate that their greatest adversary was dead, he still insisted on making sure by trying to check for a pulse himself. Hange, convincingly, assured them that Levi was dead, then seized an opportunity to escape when Zeke emerged from the body of a dead Titan.
Thunder Spears are powerful enough to blow the armor off Reiner Braun's Armored Titan, so how could Levi have possibly survived one exploding in his face? As a descendant of the Ackermann bloodline, Levi is far stronger than the average human. The Ackermann Clan were once warriors who protected the king, capable of manifesting the strength of Titans in human form. And still, it apparently took every ounce of Levi's superhuman strength to cling to his life after such devastating injuries. In all honesty, he almost certainly would have died anyway if Hange had not found him.
So, what does it mean for the series now that humanity's greatest soldier has returned, albeit unconscious? Eren has left Paradis Island while killing countless Eldians with the Rumbling, while the Jaegerists, led by Floch, are violently seizing control of the war-torn island. Paradis' military is all but gone, including Nile Dawk and Dot Pixis, the commanders of the Military Police and Garrison respectively. Keith Shadis, head instructor for the military, has no plans to rebel, meaning there's no one else to stop Floch's power grab. Levi might be the only symbol left whom the remains of Paradis' military could rally behind to fight back against the Jaegerists.
As Armin Arlert pointed out, there is absolutely nothing they can do about Eren and the Rumbling right now. Even if there were, Levi's fighting days are most likely behind him. Much like when Erwin Smith lost his arm, Levi almost certainly won't withdraw from the front lines, but his leadership is now the most important contribution he can make as everyone struggles with the magnitude of what Eren has done. There's little reason to believe that Levi would support using the Rumbling to wipe out all life beyond Paradis Island, even if for no other reason than to oppose Eren, in whom he has lost all faith.
Given that Hange peacefully approached Pieck and Magath, the people who just invaded Paradis Island and slaughtered its soldiers, the 14th Commander of the Survey Corps may be seeking an alliance. If such an alliance could lead to stopping Eren and finding Zeke, Levi surely wouldn't let a few missing body parts stop him from hunting down the fur ball Titan he hates so much. After all, Levi still has a promise to keep to the late Erwin Smith. Killing Zeke Jaeger might not help stop Eren, but it would sure make Levi feel much better.
