This is one of my original, collectible ACEO Art Cards. ACEOs measure just 2.5 x 3.5 inches and they're a great way to create, collect and trade original artwork. You may visit Art-Cards.org to find out more about these mini-masterpieces.
Oaksten is a young Tree Ent of the Oak variety. He's a forest guardian and protector... something along the lines of the Greenman of Celtic mythology or Tolkien's Ents.
This piece was auctioned and sold to a private collector on eBay.