Insert Saitama into the first series that comes to mind (OPM excluded)

[AquaWaifu]

He is treated as a giant NLF that is unaffected by any being in that series, even if they be tier High 1-A or 0. Basically his NLF status on the internet is treated as if it were actually true.


How do the characters react to him?

My choice:

Dragon Ball Super

 

[Gemmysaur]

Dansai Buri no Crime Edge

Something something long, lush, beautiful hair and a haircutter with a magic scissor to cut that hair.

It's not a matter of how people react to him, it's a matter of how jelly he gets of hair.

 

[Jiangshi1]

Bobobo-bo Bo-bobobo


Its just a comedy waiting to happen, especially with Bobobo mistaking him for one of Czar Baldy Bald's goons.