Well thats interesting a lot more defined than your other sketches.

The alchemist skeleton is awesome because it made me smile looking at it. Just the idea of a skeleton holding up a vial and going 'Aha! I've done it!" just got me.
The only crit I'd really have is to be consistant - not so much in the colouring but the drawing itself. I'm referring to his hand because while the rest of him is made of bones, his hand looks like a normal fleshy one.

As for Linebeck, I've only seen a few pictures of him since I haven't played the game he's from but he does look like what I've seen. A good rendition of him. What I would suggest is to even out the colouring. Some of it is really splotchy and dark, like the are on his cheeks. Its too dark and burnt looking, what you should do it get something like a soft edged brush, lower the opacity on it and select a surrounding colour and gradually work over the burnt areas. If you keep selecting back and forth between colours you'll get a nice smooth color gradient kind of look.

That being said, use the burn and dodge tools lightly. Burn is great for lightly darkening areas but don't go overboard with it. It's a simple matter to add it lightly, select that new colour it creates and use that to make a gradual shadow as you keep upping the burn one step at a time.

Hope that wasn't too confusin ^_^;

__________________

RIP Duke
BA Characters:
Joker Kyralie Calista
Artwork - No requests =(