So I'm a Spider, So What? - Kumo Desu ga, Nani ka?

[DarthEnderX]

I meant to say that the voice doesn't tell people to kill Taboo users or give instructions - so I initially didn't even think that they were worshipping the Lvling up voice.

No, what I think is happening is that there is a regular-ass religion with a god that she was raised in. Then she hears the system voice and then goes "This must be god!"

And I DON'T think the voice is telling her to kill people. The way it seems is the voice tells her about skills, she sees one called Taboo and thinks "God is telling me this is taboo. So it's forbidden. So everyone that has it must die." because she's a fanatical psycho.

also we don't know if everyone has access to the same skill set menu.

Are we sure the locals even HAVE the voice? Maybe the system is only accessible by otherworlders.

And even if they did, without our real world video game context, yes, locals would assume the system is a god.

Well, since you mentioned "Hero" (a lesser known kind), that to me seemed to entail some sort of Title.

In JRPGs though, "Hero" is usually a class. Especially in Dragon Quest, which is the main influence for all these isekai.