Creating Extreme Characters that look Real

Many readers want to identify with the characters they read about in fiction. They want them to be real enough to their own world. But it sometimes happens in fiction, that what is truly real, seems too fictitious to be fiction. For fiction to seem real, most of the time it needs to not be so real....for some readers, and some genres.

Sometimes the writer wants to take the reader to a dimension beyond what is real in a normal, average world, yet within the realms of reality. i.e. not science fiction or fantasy fiction.

The writer will create characters with extreme behaviours which will seem unbelievable to some. Maybe the character is mentally ill, but not yet diagnosed, and the writer makes no mention of a diagnosis, because it is not part of the plot. Remember, this is also true to life. There are many mentally ill that walk amongst the normal people in the world. Because of this the reader should be prepared to be taken on a journey beyond their own experience, in order to experience the thrill of another person's mind - the writer's mind, and the character's mind. But first the writer must prepare the reader in the first chapters.

Often writers will take such characters from real life, examine their characteristics, their motives, and  behaviours, and imagine them at work in the real world, then transport them into their work of fiction. 

I feel that to make these characters real, they must be transported as a whole person, ready made, into the  fictitious world we've created. But first we must examine their motivations and how they would react given each situation in this world. To the reader, it must all seem viable. So the world around them must be real, and one identifiable by the reader. That way, the reader is grounded in the real world while the unstable eccentric character plays his part. The reader then sees him clearly for what he is, psychotic or extreme, mentally ill, or clown. He plays his part against the backdrop of a world that is real enough for the reader to identify with. 

Creating real but extreme characters is not easy. And requires close scrutiny into the mind of the type. The more complex, the more difficult to make it real. So some aspect of the situation has to be normal and easily identifiable with. That, I suggest, has to be the world he is in.