Nekomata, Ghost, or a Detective's Assistant?

So, for my story, I have a Main Character. 3 of them, actually. Anyways, the story is divided into 3 parts(1 part for each main character), and the first part involves an Ordinary High School Boy and his Watson sidekick. Now, I want to make this mystery story kinda supernatural somehow. Not so much that it ruins the story, but enough to make it almost like how Bakemonogatari or The Longing of Shiina Ryo was.

Now, for the Watson, I don't know what to make her be. Should I have her be a 100 year old Nekomata? A ghost that recently died? Or should I make her a normal detective's assistant whom ran away and met the Protagonist by chance, and push the supernatural elements to another character completely. It's been really bothering me for some time now, what to do with her...Either way, she's gonna be a recurring character in future volumes, so I kinda want her backstory to be something that's not revealed in 1 episode and such.

And yes, she's a possible Love Interests for the main character, but not the victor to the upcoming Love Triangle.

EDIT: Also, does this problem even warrant its own topic? Should I have just gone and ask in the Random Questions thread instead?

edited 3rd Oct '12 8:24:36 AM by danna45

Since they're so specific and would go into different directions, we can't really tell you what's best. All I can say is to pick one and stick to it.

Quite simply, whichever is going to give the most interesting plots and interactions with other characters.

I might be a little late for this, but the role of a Watson usually is very simple: to add some sort of sense to a genius' work. In order to achieve balance, one of the characters must not be as ridiculously brilliant (or at least not as eloquent) as the others, but can offer down-to-earth insight by considering on the big picture, as opposed to a savant detective's tendency to focus on one aspect and blocking out the rest. Usually, the more normal the better but you can add a good twist if the assistant, a supernatural creature of sorts, is constantly surprised by how ruthless or wicked the detective's mind can be even in comparison to their own; human imagination can go down some very, very dark roads at times.