Yep, that's Yakumi Sarai for ya. I've never been a fan of how quickly their doujins shift their tone, personally. In this case, it goes from lighthearted to drama to crying blood and hellfire to creepy and back to lighthearted. I can't get a fix on Suwako's personality, either, given that she apparently enjoys occasionally decimating a village with fire, but is still supposed to garner sympathy.