A big question in My Hero Academia is whether or not Mirio Togata should've been the OFA successor.
Long before All Might ever met Izuku Midoriya, he strongly considered giving his OFA Quirk to Mirio. It's not just anybody who can become the successor. Mirio was strong enough to rival Japan's most powerful heroes. His creative fighting style involved the ability to phase through objects.
After Mirio lost his powers in the Shie Hassaikai arc, Midoriya considered giving the OFA Quirk to him. Mirio politely declined, however, since he believed in Midoriya. Of course, some My Hero Academia fans believed he should've taken the offer, but that's not what the story is about.
Note: This article will contain major spoilers from the manga.
Would Mirio have been a better OFA user in My Hero Academia?
Midoriya certainly thinks highly of Mirio if he really wanted him to have his OFA Quirk. However, everything turned out for the best in My Hero Academia. Based on manga revelations, this article will discuss why Mirio wouldn't have been the right successor.
Mirio certainly would've been a powerhouse
Permeation is a Transformation Quirk that breaks the laws of physics. Mirio can phase his entire body through physical matter. He can also selectively choose which body part receives this special treatment.
Mirio could effectively dodge attacks from any direction. Since his body cannot overlap with matter, he could repel himself through surfaces at blinding speeds. Mirio is like a collision detection glitch in My Hero Academia.
While he is already physically fit, the OFA Quirk would make him even stronger. Mirio could land devastating blows that would destroy giant robots. With the ability to phase through matter, he would have the ultimate offense and defense.
However, his lifespan would've been shortened dramatically
My Hero Academia Chapter 304 dropped a very important revelation in regards to the OFA Quirk. There is a reason why All Might and Midoriya lived much longer than their OFA predecessors.
All Might and Midoriya were born Quirkless in My Hero Academia. This ended up saving their lives in the long run. Previous OFA users already had another Quirk. However, their bodies couldn't handle multiple at the same time, so this resulted in their shortened lifespan.
This wasn't discovered until much later in the series. Had Mirio inherited the OFA Quirk, he would've lived a short life. The young hero would've been a broken fighter, but not for very long.
It's a good thing that Izuku Midoriya inherited OFA
In the end, it all turned out for the best. Midoriya proved himself to be a very capable hero with the OFA Quirk. Meanwhile, Eri would later restore Mirio's powers during the Paranormal Liberation War.
Mirio had the right mindset when he rejected Midoriya's offer. The best part is that it wasn't for selfish reasons. Mirio genuinely believed that Midoriya would become a great hero in his own right. His very humble nature unknowingly saved his life.
Note: This article reflects the writer's personal views.