So, there aren't any victims. I guess there is a reason why he has the title of the strongest.
No victim huh. Not as hypocritical as I thought.
Isn't this guy extremely confident. After all that, he's either a fool, or that strong for not believijg Yayoi could kill him someday
I guess it's more his own confidence in his strength than in his underestimating her. He can do more than Yayoi at the same age, has more knowledge and experience, and from the last chapter, we know he is a hard-working genius, too. Even if she trains as his pupil, there is a big difference in the time spent honing their abilities.
On another note, she will definitely agree to become his pupil. Although she has been doing fine for two years with what she knows, in this chapter, she is forced to realise that she is still lacking specialised knowledge. Yayoi already acknowledges this after the battle with Taisai, and Oobashi is an Onmyouji, a specialist who can create a contract with a spiritual being and use them as shikigami to fight, just like Yayoi did.