NIGHTEYE SETS OUT TO CONTINUE ONE FOR ALL’S LEGACY BUT PASSES ON HIS OWN LEGACY INSTEAD.
He see’s Mirio’s potential and takes him on as a student. The predictive combat strategy he teaches him, mirrors Nighteye’s own personal methods.
It’s clear that Mirio had trouble with his quirk even while enrolled at UA. He was able to fully become Lemillion, by applying the lessons he learned from Nighteye. This super move?
We know that Mirio’s quirk is very complex. When he phases parts of his body they become virtually non-functioning. He more than likely worked with Nighteye to develop it while accounting for all the fine details the move involves.
And of course there’s this panel:
There’s a lot that we don’t know about Nighteye and Mirio’s student-mentor interactions. But we know they were close. Mirio pleaded for Nighteye to live because there was still so much more he wanted to learn from him.
Mirio is resolved to be the “outstanding hero” that Nighteye foresees he will be. And to do it, he’s going to be using those methods and strategies Nighteye taught him.
To do it, he’s going to keep smiling.
Sir’s original intention was for Mirio to inherit One for All. But the strong hero that is and will be Lemillion exits because of the legacy of the pro hero Sir Nighteye.