Copic does make inking pens, as well as markers. And their markers are worth every goddamn penny, so much fun to color with.

And instead of just a brush pen - which in my experience have always been kind of novel, and it's nice that you don't have to clean up but never something you'd really want to use on a finished piece - you might consider getting a watercolor brush and a nice bottle of india ink. If you have the money I'd recommend Windsor and Newton Series 7 Brushes, but almost any brushes that you find at your art store will work. As for ink almost any india ink is good, I think I use Higgins but am not 100% sure. I know some artists such as Jim Lee like to use something like this, and they just pour the ink on their paper and spread it out.