Kumo-chan is a very good main character, at least in my opinion. Her ability to beat the odds and attempt to strategize during a fight makes her eventual escape into the overworld extremely satisfying to read. She has a personality, a lot of spunk and the ability to think quick on her feet, which makes every successful battle not only satisfying (due to her being born weak), but believable too. Not to mention the current chapters are popping the fuck off. If you have the time, please give Kumo a read.
Kumo desu ga, nani ka?