I keep wondering how much, if at all, this was inspired by Fujimura-kun Meitsu. It's sort of as if Helmet got a spin-off manga and was promoted (or demoted, as the case might be) from boke to tsukkomi.
Manga
Never heard of this series before so I'm just going off of the description but I don't really see it?
Alvin is neither a loner (he's a beginner adventurer who sucks, that's why he's alone) nor a delinquent (he's a really nice guy to pretty much everyone) and while I understand the boke - tsukkomi transition, complete change of character would be a bit much for such comparison, wouldn't it?
That said, I might be completely wrong since I know nothing about the other manga. Is it any good?
Ah - I thought to explain the connection, but didn't want to belabor the point if you already got it.
First and most broadly, Fujimura is a tsukkomi completely surrounded by bokes, much like Alvin.
More curiously though, there's a side character who's just called Helmet because he's never seen without a full-face helmet, just like Alvin. And even to the point, again like Alvin, that in the rare event that he isn't wearing his helmet, his face is pointedly hidden anyway.
On the one hand, that's a sort of meaningless detail, but on the other hand, it's a meaningless detail that matches up between the two. It seems too insignificant to be deliberate but too obscure to not be.
And yeah - it's good. It's mostly the same sort of boke and tsukkomi humor as this, and with really good characters (the fmc - Eri - is still one of my all-time favorite manga characters). And it's also a surprisingly effective harem series, since the girls are all bokes of one sort or another, which is an alternative reason for them continually pestering Fujimura, and he can't help but tsukkomi, which explains the otherwise awkward harem contrivance of the MC generally not figuring out what's going on. It's not so much that he can't figure it out as that he can't take it seriously - he thinks they're just sort of deranged. And he's not entirely wrong.
Oh, OK. I thought by "Helmet" you meant Alving rather than a different character, makes more sense.
Guess I'll add it to the pile.