As a character designer, I try to always make sure that my characters have a sense of soul. You can have a great character designs, but it can still feel soulless. In order to create a truly charismatic character the designer really has to invest their own emotions. You need to be passionate. If you just produce characters because it's your job and you don't really have affection for what you create you won't be able to create. You need to enjoy the characters you create, in order for them to have a soul.