A character designer(or character artist) creates the entire concept, style, and artwork of a character from scratch. This often includes a deep look into the character’s personality to develop a visual idea of the character’s physical features.
Creating an entire character from scratch(human or otherwise) takes a lot of creative energy.
That’s why the process of character design is very complex and is often one of the most sought-after careers for aspiring entertainment artists. Every artist has their own creative process so there is no “right way” to create a character.
But typically the character design process starts with a briefing of the character. The character could be a mutant turtle with ninja-like abilities, or just some person who lives a simple workaday lifestyle.
With this briefing there’s often a series of suggested traits be they physical or emotional, and the character designer uses those notes to start thumbnailing ideas. Rough thumbnails help to flesh out the many directions that the designer could take.
Once the artist chooses one(or a couple) thumbnail styles they’ll often paint more details and bring those thumbnails to life. This can include trying different clothes, different hair styles, facial styles, and maybe different weapons or props if applicable.
Then a final design is chosen and once the character is signed off the artist will create many different views of the character as reference materials. In animation this often turns into a model sheet for other artists to reference in their drawings.