Lmao I don't think the artist has a nervous hand, no they have a fast hand, they can draw well, but the managa's weekly, so they have to pump out results vs. Rendered perfection. Artists all draw at different levels, pouska's strength lie in illustration and fisheye for environments, they're not as interesting in a super consistent figures art wise like other shounen series ( black clover/Dr. Stone), but I do think some of the inconsistency's are on purpose (Norman's age/size for eg is supposed to look different then Emma, we we're supposed to feel the uncertainty if it was him as he acts more like an adult at this point then the other teenagers).