Cooked up a few things while at work.

The standard Arthur sprite, as requested. However, the bosses tend to be a bit bigger and meaner. Therefore, I imagine Arthur suddenly gets possessed by some demon thing after the initial fight and then mutates into:

Demon Arthur! (Insert dramatic music).
Didn't really plan his looks, just made it up as I went along. Noticed he looks a bit like nightmare from Soul Calibur, but no matter. All the colours were taken from the Arthur and Demon sprite because I haven't figured out how to get pure 16 bit colour yet. (I've never needed to).
The DC style has a lot of pillowshading and a lot of contrasts, something I'm not a big fan of. I kept the contrasts, but I've purposely avoided pillowshading as long as it somewhat still resembles the style. Feel like I need to wash my hands or something...