I suppose you could call this style western manga. Sepia Drawings are really cool and it's something I did a little of in high school. My base preferences have always leaned towards 'cartoony' so adopting my own version of manga wasn't too hard.
What I feel sets the manga style apart from sepia is simplifying complex components of an image. Example: when drawing hair, rather than emphasizing each strand of hair it gets simplified into several solid masses. The same can be said about skin, clothing, etc.
I used to copy images of people from magazines or models in art class. I also copied artwork from video games like Street Fighter and Darkstalkers. At one point I felt my style was becoming too bland so I reverted into extremely simple shapes and rebuilt my style off of that. I still struggle with hands, feet, and noses so I wouldn't call my style completed as of yet. The 'How to Draw Manga' books were a big influence as well.
When I have more time I'll try to find an example of what I mean; I've saved a lot of my old, old works from when I was a teenager. You can even see the progression of my style in what I've posted in this thread.