WIP Challenge Day 26: Which comes first? The character's story or the idea for the novel?

For me, the idea of the novel comes to me first and as I begin writing it, the character begins to speak to me and tell me his/her story. Just this week I began working on a new wip, and already having the idea in place it seemed like everything else came naturally. I could even see a clear picture of what I imagined the main character looks like, and when that happens it's a good thing. It gives me hope that this book will turn out good.
A lot of good writing with me is usually based on instinct. I try to trust it most of the time, even when I cannot for the life of me figure out why the character is taking me on this path, instead of the one I originally envisioned. Most of the time it eventually makes sense, and excites me.
Sometimes, the character's story and the idea is intertwined, especially when a certain person inspires a character. Obviously you are already going to have their story down pat for the most part, the fun part is weaving it into the storyline of  the novel.

This is a t-shirt I bought at Paramount's King's Island years ago. My first writer shirt ever.