Avatar: The Last Airbender features Avatar Aang as the hero, a cheerful pacifist monk boy who can bend all four elements as the Avatar. He has a mission: to master those elements, defeat Fire Lord Ozai, and end the Hundred-Year War at last.
Aang has the brother/sister duo Sokka and Katara to help, along with Toph the Earthbender and later, Aang's former enemy prince Zuko to help. If Aang had the chance, he would also recruit a few heroes from Japanese anime to help, and they must be ready to travel all over the world and fight the Fire Nation at any turn.
10 Izuku Would Become The Symbol Of Peace Alongside Aang (My Hero Academia)
Izuku Midoriya is determined to become the next symbol of peace, and helping the Avatar end a global war should do the trick. Izuku isn't particularly tied down to any location or person, so he would be free to wander the Avatar world for months or even a year with Aang.
Izuku is also a solid tactician and thinks ahead, like Sokka, ensuring that Team Avatar would be prepared for absolutely anything. Then, if Azula or Fire Nation platoons show up, they'll get blown away with Detroit Smash.
9 Diane Is A Titanic Earthbender (The Seven Deadly Sins)
Diane is a giantess from the land of Megadozer, and with her giant hammer Gideon, she can reshape the earth around her, even small mountains. This makes her an incredibly powerful Earthbender of sorts, and even Toph Beifong would be in awe. Diane can't bend metal like Toph, though.
Unlike most Megadozer giants, Diane is a bit of a pacifist and seeks to defend her allies rather than seek glory in battle. But she would join Aang to help end the Hundred-Year War so no one else has to suffer. Naturally, she'd stay in her human-size form until a battle begins. Her normal form would make it too easy to find Aang.
8 Lucy Heartfilia Wants To See The World (Fairy Tail)
In the original Fairy Tail, Lucy Heartfilia the celestial wizard joined the Fairy Tail guild, and nothing could convince her to leave that guild. But if she had met Aang instead, she would gladly join Team Avatar and lend Aang her talents as a creative and quick-thinking wizard.
Originally, Lucy left home to explore the world and meet new people, and she would get her wish and more by joining Team Avatar. She would marvel at the Northern Water Tribe, the metropolis of Ba Sing Se, and Ember Island's gorgeous coastlines.
7 Alphonse Elric Already Stopped One War (Fullmetal Alchemist: Brotherhood)
Alphonse Elric is a kind and smart alchemist, and he and his brother Edward helped Roy Mustang and the others take down Father to save the nation of Amestris. Alphonse didn't deal the final blow, but he did contribute greatly to this endeavor, and he would do it all again if he could.
Alphonse would use his alchemy talents to protect Aang and escort him to places such as the Northern Water Tribe and the Fire Nation, and it would all be for a good cause. He'd see Ozai as one more Father to take down.
6 Naruto Uzumaki Would Join To End The Cycle Of Hatred (Naruto)
Naruto Uzumaki dreams of becoming Hokage, and he'll prove his worthiness against any foe and impress the world. He took on the Akatsuki and other foes and won, and he would also help take down the Fire Lord and bring peace back to the world.
Naruto isn't afraid of a fight, but, then again, he and Nagato both know that war only perpetuates the cycle of hatred, and nothing good can come of that. So, Naruto will risk his life to help end the Hundred-Year War and bring the nations back together as one.
5 Armin Arlert Is Used To Desperate Battles (Attack On Titan)
With or without the powers of the Colossal Titan, the soldier Armin Arlert could do a lot of good for Team Avatar since he is a skilled tactician just like Sokka. Together, he and Sokka could devise brilliant strategies to run circles around the Fire Nation army, and not even Azula or Admiral Zhao could catch them.
If Armin has the Colossal Titan form, he could obliterate entire battalions of Fire Nation forces on his own, and he could probably retake Ba Sing Se all alone. It also helps that Armin is used to fighting against enemies such as Titans and the Marley Empire, so he could use that experience to fight the Fire Nation.
4 Naofumi Iwatani Is Used To Long Journeys (The Rising Of The Shield Hero)
Naofumi Iwatani is the shield hero himself, an isekai protagonist who can summon many durable magical shields in combat. He struggled in the Melromarc kingdom due to the king and Princess Malty scheming against him, but he could get a fresh start in Aang's group.
Naofumi would welcome the chance to fight for world peace without having everyone calling him the shield devil, and he is already used to long journeys and fighting large numbers of enemies. Fighting the Fire Nation in Team Avatar should be relatively easy.
3 Princess Yona Has Been Through This Before (Yona Of The Dawn)
The shojo genre doesn't always feature warrior heroines, but when it does, the result is fantastic characters like princess Yona. She went on the run when her friend Soo-Won betrayed her father, the king, and she had an Avatar-style adventure of her own, trekking across the land and recruiting new allies along the way.
Once Yona reclaims her own kingdom, she can do the same thing for Team Avatar and embark on a similar journey. As long as people need a heroic princess like her, she will be there. And Aang could always use another ranged specialist on the team.
2 Maki Oze Can Fight Fire With Fire (Fire Force)
Originally, the fire soldier Maki Oze belonged to the Japanese army before joining company 8 of the FFS. But if that never happened, she would instead join Aang if he put out "help wanted!" flyers. Aang needs allies to save the world from evil Firebenders, and Maki is perfect for the job.
Maki has sworn to save lives and defend the peace, and helping Aang defeat the Fire Nation would save tens of millions of lives. Besides, she is a second-generation pyrokinetic, so her abilities would be the perfect counter to hostile Firebenders. She'd have fun throwing their own element right back at them in style.
1 Milim Nava Would Take This Chance To Explore & Have Fun (That Time I Got Reincarnated As A Slime)
Unlike most anime characters, Demon Lord Milim Nava would join Aang's team not to save the world or prove herself, but to have fun. Milim has nothing to prove, and she is clearly not interested in sitting still in her own domain. She needs a change of pace.
Milim would see Aang has her new bestie, especially if he bribes her with food, and Milim would have a blast goofing off in the Northern Water Tribe, in Omasu, and even on Ember Island. Aang and Sokka would really have to reign her in, or else she might attract the Fire Nation's attention one too many times.