Artist Eric Polak is new to Magic illustration as of the Saviors of Kamigawa set, to which he contributed three pieces: Raving Oni-Slave, Kitsune Loreweaver, and Seek the Horizon. Welcome to the game, Eric!
The first step of the creation of a card's art is its art description. The art description tells the artist what the card will do, what its flavor is, and what the mood of the illustration should be. Here were the instructions given to Eric for Raving Oni-Slave:
Location: Artist's choice
Action: Show a homicidal ogre of your design (see p. 67 of styleguide for basis). This ogre is completely mad. He has a brand on his forehead in the shape of a vertical third eye to show his devotion to his demon masters.
Focus: The psycho ogre
Mood: He'll do whatever his demon masters tell him to do. Until then, he'll kill whatever crosses his path.
Remember that oni, the demons of the Kamigawa plane, have a third eye to signal their nature. This ogre is not an oni, but has a third-eye brand on his forehead -- he's that crazy about his oni superiors.
Here are Eric's concept sketches submitted for Raving Oni-Slave:
Raving Oni-Slave sketch 1 by Eric Polak
This is a nicely detailed pencil sketch but with a slightly difficult perspective -- with the ogre turned away from the viewer this way, it's hard to see the center-eye brand or recognize that it represents a third eye.
Here's Eric's second sketch:
Raving Oni-Slave sketch 2 by Eric Polak
Here the ogre is shown from a front-on perspective, and you can clearly see the brand represents that demonic third eye. You can also see better in this sketch that this guy has two pairs of nostrils!
Eric submitted this final art.
Raving Oni-Slave final art by Eric Polak
In the final art, Eric added the ogre's right hand to the frame for a bit of balance, but otherwise it's spot-on to spec from his second sketch.
And here's the card in its final state, as you can see in booster packs of Saviors of Kamigawa. Beat down for 3 (and a little help from Eric Polak) with Raving Oni-Slave!