Although the story does take a darker route, and as Aricitic said she does become, from a certain perspective, the big bad, she keeps her goofy personality and the story keeps its light hearted tone for most of it. It's just that it also has some pretty heavy moments on top of that. The uphill battle's between significantly superior foes will, however, all but disappear. I don't want to spoil why, but in essence its because all her major foes either pose a threat in some way other than combat prowess, are so massively beyond her that she can't even dream of ever directly fighting them, or in one case is a superior foe that she is constantly preparing for a possible confrontation with. That confrontation would probably be the uphill battle you are looking for, but it hasn't happened yet, even in the most recent chapters in the web novel. Also don't worry, she is still a literal spider to the end, even if maybe not quite in the way she seems now.