Back in 2006, I had a small character known as Dumah: http://hunterbahamut.deviantart.com/art/Dumah-42822985 . Originally he was meant to be a 'lovechild' character between my character Zeleme and a character belonging to a friend.

At the time when I finished the original image, I was happy with it, but I noticed that the way I drew his right arm made it look like it was actually missing and I had even made note of that in the description and said that it wasn't meant to be like that.
However, that idea had stuck in my head and I started to think on it, I realized that it actually could have been a nifty idea and started to wonder how it would work.
Since I've been playing a lot of Champions Online, I actually decided to sit down and work on a version of Dumah to play in the game and they had options for robotic arms and legs, so I decided to make it official where Dumah had lost his arm, but gets a replacement. (Ironically, this was also around the time Deus Ex: Human Revolution was released, so the augmentation angle helped fuel this idea.)

Finally, I decided it was a time to do a newer and updated picture of Dumah, grown up and with his new arm.
I kept his look and colors pretty much the same, his clothing is influenced by his Champions look and the replacement arm is influenced by Deus Ex as well some artwork found in the DnD: Ebberon Player's Guide, since I wanted a look for the arm that could fit in a tech setting or a fantasy setting.

Dumah is a darkling: his father was a demon while his mother was a mortal, but his mother died during childbirth. His father tried to raise him in the Demonic Realm, but Dumah never really felt like he fit in. When he discovers the mortal world though, he developed an interest and fascination and was able to visit it a few times, actually making some friends there.
When his father discovered this, he was very angry and he imprisoned Dumah. His friends from the mortal world actually risked going in the realm of Dys and rescued him, but Dumah would fight against his father before they could escape, resulting in the loss of his arm.

Thanks to his friends, he was able to recover and actually get the replacement arm, something that he actually thought was kind of cool.
He doesn't know if his father will try and come after him again, so he started to train and work on his powers, preparing for when he would face him again.

Photoshop 7.

Dumah and artwork are mine.