How to write a novel? I know this is not my story alone.

[removed]<br><br>I have no ideas. No forms of creative writing ever interested me until I was 14 and a character invaded my minds. I knew his backstory: Suspected sociopath, 19th century vice-president of the usa, dirty dealings, nazi like president who killed his first vice-president, a married minister and her maid, an Italian Italian who is his likely step-sister. <br><br>Of the 5 years he's been living in my mind, I've struggled to have a regular conversation because he's so bizarre and illogical. I've seen visions of such atrocity, I think I may have post traumatic stress disorder. His character is based on real events of American history and he speaks in my voice as I see the world from his eyes. <br><br>He is the archetypal narcissist, living in a world of his depraved mental illness. I am convinced this is not my story yet I have no right to write it. He is the only one who knows the story that needs to be told and he is the best person to tell it. <br><br>What would you do?