Didn't he read opm? Hair loss is the first sign of unlimited power.

I wonder if the person he'd saved had been a male child if Yoru would have helped Denji save the guy while also coming to some sort of "kill people bad" realization rather than kill her. That's probably why the author made it a girl, now that I think about it...

Where is this art from? I swear I have seen it before.

I think part of it is that ALL the villain's and heroes have actually believable and empathizeable backstories. Yeah, it's turned up a notch for comedic effect, but like an office worker who delt with his backbreaking job by eating too much crab? This guy appeared for one chapter but it's totally believable that someone might get pissed at some kid for drawing nipples onto their bare chest with a permanent marker. Even Saitama doesn't actually refute the guy's anger, he just thinks the reaction is overboard. Also up until this point, all the villains and hero's have been just a little bit goofy. Blast is like the only hero in the entire hero association with actual superpowers, flashy flash is literally called flashy flash and he is just very fast, speedo sound sonic probably doesn't have balls anymore and we're reminded of that everytime we see his art, even that giant puppet leader of the monster association was implied to have once been a simple houseplant. Heck, the more awesomely drawn the character the more silly (yet believable) their backstory. Which makes it even more funny when they fight a goofy yet serious hero like spring mustachio, who understandably probably made his own spring powered sword character for marketing purposes, but it is still hilarious.

In all those other manga, the side characters are either not developed enough, have inhuman personalities, or are just too serious.