Questions About Fantasy Art Niche...

Hello...

I have a friend who's an immensely talented artist and draws great fantasy artwork (unlike me, whose level is slightly above drawing stick figures).

Anyway, I was thinking of getting together with her to sell her fantasy artwork online, perhaps maybe draw some "horror" artwork as well.

I was wondering if anyone here in this forum has any knowledge/success in the "horror/fantasy artwork" niche, and how profitable that niche is.

I know people like to look at artwork online, but are they mainly "lookers" or "buyers" (I know that just because a niche is popular doesn't mean there are buyers).

Depending on how far I go with this, I was thinking of:

(1) Selling customized horror/fantasy art shirts from TeeSpring or CafePress...

And/or...

(2) I'm starting a site that's dedicated to horror stories/books (I'm more of a writer than an artist) and was thinking of perhaps adding a separate page on my site with a store that sells fantasy/horror clothing.

I would appreciate your thoughts on these two ideas I have. Also, regarding idea #2, do you feel, perhaps it's better to have a separate site dedicated to horror stories and another separate site dedicated to fantasy/horror apparel, or is it more advantageous to combine them?

Thanks .