Kawaii characters are so cute we can't help but think of them in a positive way, and when we see an image of a kawaii character we picture them doing pleasant things and speaking with a syrupy sweet voice.
That's why one of my favorite stylistic mashups is the meeting of "kawaii cute" and "violently bloody" because it doesn't seem like a combo that would work but the two really do go well together.
Case in point- Bloody Bunny, a series that's so kawaii it will give you cavities yet so bloody it might give you nightmares, plus frenetic martial arts mayhem!