a lazy liner because I would much rather change my hand than change the brush size...
Update: added a better rough liner, and I kept the old one in case you liked it more
In simple words all you really need to know is that you can get really thin and really thick lines without changing the brush size at all
Everything (even the text) in the thumbnail is 10px (heh...)
actually now that I think about it, it was also made just so I didn't have to change the pressure sensitivity whenever I wanted to do line art
By the way, when I'm talking about 1st and 2nd in the image, I'm referring to the brushes since there's 2
Here's a demonstration of the pens (the drawing was made on an 1000px square)

Originally, I was trying to make a brush that would have taper on the end when it's straight and no taper or be blunt when it's tilted, but this is the best I could've done
I just have to tilt the pen in a very specific way if I wanted to get the effect that I originally wanted
Demonstration 2: smooth and rough lines 

Here's the updated pen:

I added another one because I figured out how to make the rough texture better looking
I might talk too much... anyways I hope you like it ^^
pens
rougher line art (update)
Update history
Added another rough pen
Old version