lmao that's because they're designed by Rui Komatsuzaki, the main concept artist for the DR series. Rui got their start doing type-moon doujin work, so that's why they did some illustrations for fgo, as nasu never forgets an artist that helped type-moon out early on. it's actually one of the really cool things about fgo, even if i don't personally care for rui's art style.