#UA existed when All Might was 15 so its not much of a stretch to think En couldve been a hero course student

[mishy-mashy]

En was killed by being cut in half by AFO. It wasn't that he couldn't handle OFA, but that AFO just decided to nuke him

All Might says using One For All with an untrained body would make your limbs fly off. But

This isn't his limbs? Yes, that's his arm, but that's HALF OF HIS BODY

Yes, there's also the argument he could've used it on his whole body and that's the consequence but there is a small cut on his thumb. It matches the line in which he was cut in half, and blood spurts from his hand.

The translation hides it, but his thumb got cut too from the slice. His thumb wasn't the focus, but still got hit. It at least shows when En passes on OFA to Nana

Since Banjo's arms got wrecked by using OFA, maybe En used it in one leg and that's why his leg is differently-colored and looks more beat up. En probably couldn't handle the Quirk either.

This means that En was being logical and saw OFA as a tool, and only used it in a leg so he could run.

All Might specifically says an unprepared vessel's limbs will fly off. Even if En used it on his whole body, that means only his arms and legs; but that's his torso. His leg didn't go flying either; at least until they both went flying cuz he was severed.

[lost-in-the-echo-94]

My top 10 favorite shōnen and non-BL mangas

1) Naruto / Naruto Shippūden -  Kishimoto Masashi (manga/anime)

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Summary : Twelve years before the start of the series, the Nine-Tails attacked Konohagakure destroying much of the village and taking many lives. The leader of the village, the Fourth Hokage sacrificed his life to seal the Nine-Tails into a newborn, Naruto Uzumaki. Orphaned by the attack, Naruto was shunned by the villagers, who out of fear and anger, viewed him as the Nine-Tails itself. Though the Third Hokage outlawed speaking about anything related to the Nine-Tails, the children — taking their cues from their parents — inherited the same animosity towards Naruto. In his thirst to be acknowledged, Naruto vowed he would one day become the greatest Hokage the village had ever seen (source).

2) Boku no Hero Academia -  Horikoshi Kohei (manga/anime)

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Summary :  One day, a four-year-old boy came to a sudden realization: the world is not fair. Eighty percent of the world's population wield special abilities, known as "quirks," which have given many the power to make their childhood dreams of becoming a superhero a reality. Unfortunately, Izuku Midoriya was one of the few born without a quirk, suffering from discrimination because of it. Yet, he refuses to give up on his dream of becoming a hero; determined to do the impossible, Izuku sets his sights on the elite hero training academy, UA High. However, everything changes after a chance meeting with the number one hero and Izuku's idol, All Might. Discovering that his dream is not a dead end, the powerless boy undergoes special training, working harder than ever before. Eventually, this leads to him inheriting All Might's power, and with his newfound abilities, gets into his school of choice, beginning his grueling journey to become the successor of the best hero on the planet (source). 

3) Shingeki No Kyojin -  Isayama Hajime (manga/anime)

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Summary : Centuries ago, mankind was slaughtered to near extinction by monstrous humanoid creatures called titans, forcing humans to hide in fear behind enormous concentric walls. What makes these giants truly terrifying is that their taste for human flesh is not born out of hunger but what appears to be out of pleasure. To ensure their survival, the remnants of humanity began living within defensive barriers, resulting in one hundred years without a single titan encounter. However, that fragile calm is soon shattered when a colossal titan manages to breach the supposedly impregnable outer wall, reigniting the fight for survival against the man-eating abominations. After witnessing a horrific personal loss at the hands of the invading creatures, Eren Yeager dedicates his life to their eradication by enlisting into the Survey Corps, an elite military unit that combats the merciless humanoids outside the protection of the walls. Based on Hajime Isayama's award-winning manga, Shingeki no Kyojin follows Eren, along with his adopted sister Mikasa Ackerman and his childhood friend Armin Arlert, as they join the brutal war against the titans and race to discover a way of defeating them before the last walls are breached (source). 

4) Black Clover -  Tabata Yuuki (manga/anime)

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Summary :  Asta and Yuno were abandoned together at the same church, and have been inseparable since. As children, they promised that they would compete against each other to see who would become the next Emperor Magus. However, as they grew up, some differences between them became plain. Yuno was a genius with magic, with amazing power and control, while Asta could not use magic at all, and tried to make up for his lack by training physically. When they received their Grimoires at age 15, Yuno got a spectacular book with a four-leaf clover (most people receive a three-leaf-clover), while Asta received nothing at all. However, when Yuno was threatened, the truth about Asta's power was revealed, he received a five-leaf clover Grimoire, a "black clover"! Now the two friends are heading out in the world, both seeking the same goal (source)!

5) Noragami -  Adachitoka (manga/anime)

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Summary :  As a relatively unknown minor deity without any worshippers, Delivery God Yato takes on odd jobs for only five yen, with the goal of amassing a fortune large enough to buy himself a shrine. But in addition to obscurity, he has another problem: his "Shinki," or weapon partner, has decided to resign, tired of being with a homeless god. Left with no weapon, Yato takes on more jobs, hoping to find a new partner soon. While out putting up fliers for a missing cat, Yato sees said cat and chases after him, right into the path of an oncoming vehicle. Hiyori Iki, a nearby girl, rushes to push Yato out of the way and ends up hurt herself. After waking up in the hospital, she discovers the incident has knocked her soul loose from her body. Realizing his actions caused this, Yato promises to help return Hiyori to normal—for five yen of course. But in order to return her to normal, he requires a new Shinki, which he finds in the rebellious spirit Yukine (source).

6) Ao no Exorcist -  Kato Kazue (manga/anime)

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Summary : After a fight with his foster father Shirou Fujimoto, Rin Okumura's life is transformed overnight when Rin is revealed to be the son of the demon lord Satan, king of the demonic realm of Gehenna. Soon after, his foster father becomes possessed and dies at the hands of Satan, leaving Rin and his twin brother Yukio alone in the world. Seeking revenge for Fujimoto's death, Rin attends True Cross Academy with Yukio in order to become an exorcist and join the Knights of the True Cross. Rin's new path, however, is filled with many difficulties. While new classes and dealing with his peers are already troublesome enough, he is also forced to conceal his newfound demonic powers and parentage. In addition, plenty of evildoers want to use him for their own ends. One misstep could lead to disaster, as not everyone at True Cross Academy is exactly who they seem to be (source).

7) Mahou Tsukai no Yome -  Yamazaki Koré (manga/anime)

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Summary : Chise Hatori, a 15-year-old Japanese girl, was sold for five million pounds at an auction to a tall masked gentleman. Abandoned at a young age and ridiculed by her peers for her unconventional behavior, she was ready to give herself to any buyer if it meant having a place to go home to. In chains and on her way to an unknown fate, she hears whispers from robed men along her path, gossiping and complaining that such a buyer got his hands on a rare "Slay Vega." Ignoring the murmurs, the mysterious man leads the girl to a study, where he reveals himself to be Elias Ainsworth—a magus. After a brief confrontation and a bit of teleportation magic, the two open their eyes to Elias' picturesque cottage in rural England. Greeted by fairies and surrounded by weird and wonderful beings upon her arrival, these events mark the beginning of Chise's story as the apprentice and supposed bride of the ancient magus (source). 

8) Made in Abyss -  Tsukushi Akihito (manga/anime)

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Summary : The Abyss—a gaping chasm stretching down into the depths of the earth, filled with mysterious creatures and relics from a time long past. How did it come to be? What lies at the bottom? Countless brave individuals, known as Divers, have sought to solve these mysteries of the Abyss, fearlessly descending into its darkest realms. The best and bravest of the Divers, the White Whistles, are hailed as legends by those who remain on the surface. Riko, daughter of the missing White Whistle Lyza the Annihilator, aspires to become like her mother and explore the furthest reaches of the Abyss. However, just a novice Red Whistle herself, she is only permitted to roam its most upper layer. Even so, Riko has a chance encounter with a mysterious robot with the appearance of an ordinary young boy. She comes to name him Reg, and he has no recollection of the events preceding his discovery. Certain that the technology to create Reg must come from deep within the Abyss, the two decide to venture forth into the chasm to recover his memories and see the bottom of the great pit with their own eyes. However, they know not of the harsh reality that is the true existence of the Abyss (source). 

9)  Kujira no Kora wa Sajou ni Utau -  Umeda Abi (manga/anime)

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Summary : Chakuro is the 14-year-old archivist of the Mud Whale, a nigh-utopian island that floats across the surface of an endless sea of sand. Nine in ten of the inhabitants of the Mud Whale have been blessed and cursed with the ability to use saimia, special powers that doom them to an early death. Chakuro and his friends have stumbled across other islands, but they have never met, seen, or even heard of a human who wasn't from their own. One day, Chakuro visits an island as large as the Mud Whale and meets a girl who will change his destiny (source). 

10) Suijin no Ikenie / no Hanayome -  Toma Rei (manga)

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Summary : The story of a girl who slips back in time to a different era. While playing in her family's garden, Asahi gets sucked in by the small pond and when she wakes up she finds herself in a place that seems like Japan from ancient times. A powerful clan takes her in, but the reason for their kindness is that they intend to sacrifice her to the water god, the dragon, to be his bride... Now that she is at the mercy of a god who appears to know no compassion, what will Asahi's fate be (source) ?

I also recommend you :

RELIFE (webtoon/anime)

One Punch Man (manga/anime)

Bungou Stray Dogs (manga/anime)

Ajin (manga/anime)

Vanitas no Carte (manga)

Death Note (manga/anime)

Black Torch (manga)

...