This is a complicated question because there may be many different characters in different novels. The following are some possible female characters who can be addressed as Mr.: Female authors may address their readers or assistants as "sir." 2. Male NPC(Non-Human Character): Some male NPCs may address their characters as "Sir". 3 Other male characters: Other male characters may use "sir" to address their characters. It should be emphasized that the names of these characters did not necessarily represent their personalities or character settings. It was just a way of addressing them in the novel.