Sometimes, a supporting character in anime might outshine the protagonist during battles, and in Attack on Titan, Captain Levi Ackerman steals the show. He's a Scout leader with incredible combat and leadership skills, and he has fought, and defeated, more than one of the Nine Titan Shifters.
Meanwhile, in Demon Slayer, Inosuke Hashibira nearly rivals Tanjiro Kamado on the battlefield, and he has a unique fighting style known as Beast Breathing, which he developed himself. Inosuke is always determined to prove himself the best, so much so, he'd likely take on the seemingly frail Levi and challenge him to a fight; however, would he be able to win?
Levi Ackerman: Humanity's Strongest In Attack on Titan
Levi grew up with very little in the Underground, and at first, he seemed destined to never amount to anything. Then Uncle Kenny took him in and began training the boy in self-defense. Levi quickly absorbed these lessons, learning how to wield knives and swords to great effect, and he later underwent formal training to become a Scout. Levi may have a small body due to malnourishment, but his size doesn't hold him back. In fact, it may make him more agile and harder to hit.
As a Scout commander, Levi is equally adept on the battlefield and behind a desk as a leader and tactician. Levi has sharp intuition and insights, allowing him to predict his enemy's move and find their weakness before striking. Levi is also coldly pragmatic, as he's willing to take calculated risks and cut his losses if need be, all for the sake of the mission. Levi won't risk his own life unless he absolutely must, but if it comes to that, he holds nothing back.
In combat, Levi's agility, maneuverability and speed with ODM gear are all unmatched, and even Mikasa Ackerman, herself a formidable fighter, can't quite match what Levi is capable of. He can effortlessly weave through a forest or a squad of Titans on both offense and defense, and he can take out Titans before anyone even realizes what happened. In the past, he's taken out a small handful of Titans in the blink of an eye, and when facing a Titan shifter, such as Zeke's Beast Titan or Annie's Female Titan, Levi can deliver a flurry of blows on the Titan's weak points, taking it down.
Inosuke Hashibira: Going Beast Mode in Demon Slayer
So far, Inosuke's list of qualifications and accomplishments is shorter than Levi's, but he is still a highly capable fighter. He is a demon slayer, sworn to take down demons at the risk of his own life, and he gladly faced the Lower Moon One, Enmu, in Demon Slayer: Mugen Train. However, he was not formally trained, like Tanjiro was; Inosuke is self-taught.
Inosuke is a wild one, having grown up surrounded by animals rather than people, and he developed his own breathing form: Beast Breathing. This, combined with his two jagged Nichirin blades, allows Inosuke to deliver savage blows to the enemy with surprising strength, speed and agility.
He operates mostly on predatory instinct, with his Breast Breathing forms often imitating the fangs, talons or tusks of powerful animals. Inosuke isn't an advanced tactician, but his instincts allow him to see through an opponent's strategy all the same and figure out their weakness before striking. That's what's he did against Enmu, figuring out that demon's weak spot even before Tanjiro.
Levi Ackerman Vs. Inosuke Hashibira - Who Wins?
Levi has a slight disadvantage, since he is more used to fighting Titans than other swordsmen, though it's not that difficult for him to adjust to Inosuke's fighting style. At first, Levi would struggle a bit against Inosuke for this reason, and he'd likely underestimate Inosuke's reflexes and technique. In light of this, he would be furious when the seemingly boorish Inosuke lands a few blows with his jagged swords.
Levi would then use anything and everything on the battlefield, such as sparse trees or walls, to maintain his 3-D advantage over Inosuke, and he'd use his best moves to simply outmaneuver Inosuke and land a blow of his own. Inosuke would be desperate and launch a few all-or-nothing Beast Breathing moves to try and take Levi down, but it'd be no good. Levi would see right through blunt attacks like those and cut Inosuke down before he realizes what's happening, thus making Levi the winner.