Going against the normal convention that the strongest characters should be the largest in terms of physical size, he designed many of Dragon Ball's most powerful characters with small statures. He later explained that he had Goku grow up as a means to make drawing fight scenes easier, even though his editor was initially against it because it was rare to have the main character of a manga series change drastically. The reason there are many anthropomorphic characters is simply that he finds it easier to make them look different if they are animals rather than humans. For the female characters, Toriyama created women he deemed "beautiful and sexy", but also "strong". He did however state that he has trouble drawing females and this is the reason there are few women characters in the Dragon Ball series. During the second half of the series, Toriyama placed less emphasis on the imagery, simplifying the lines and sometimes making things "too square"; found problems determining the colors; and sometimes altered them mid-story.