Law of Anime/Manga - The more popular a theme is the more it will be ripped of. Case in point - characters screaming their damn fool heads off for pages on end which started in DB. A non-DB example is Mikasa(sp?) from Attack on Titan. It's canon she has six-pack abs then just like that other mangas started showing female characters with six-pack abs. Then there is the super rapid rise of Isekai and Fantasy manga no doubt because of Fairy Tail.