The characters from this web comic are from the novel 'The Circle Theory'.
Here's the synopsis, found on lulu.com:
'Meet Tarald, an encumbered yet charismatic hero, and journey with him as he transcends from the mundane to the sublime. During his adventure he will attempt to overthrow a despotic nation, be consumed by a forbidden love, and face his greatest fears in the form of the Fell Cats, evil beasts who walk like men. A meditation on archetypes and symbols cleverly disguised as a fantasy story, The Circle Theory will entertain on many profound levels.'
You can find the book here in paperback, hardcover, and PDF format.
Also available as an ibook.
And for the Nook.
The Circle Theory gives a great backstory to the world and characters found in this web comic.
It also includes a map of the world, which will actually be helpful as you follow along with the comic.