My Hero Academia fan illustration showcasing a fan theory known as the Vault Door Theory.

After the vault door deep inside One For All's inner world opens, revealing a remaining piece of All for One's consciousness to have been trapped behind it, and leaving him free to attack Izuku Midoriya from the inside, our hero, with the help of the spirits living inside him and his opponent, gains the upper hand and takes the enemy's power into his own hands. He has the opportunity to end this once and for all. But will he, knowing it might be too much for his already damaged body to handle?