http://mmos.com/wp-content/gallery/knights-fable/Knights-Fable-Earth-Fight.jpg

these are probably 2d because it is a browser game but are they drawn in 2d or where they developed in 3d and then turned into sprites?

also any idea on how much would an artist cost to develop something as detailed as the big demon guy ?

I would say 3d models, based on the shadows I see.
My expectation is also that ingame the models animate/ rotate, like meshes, not sprites.

For me it would take like forever, since I'm no modeler :)

Funny, I was gonna say they were 2d, because of the lack of proper shadows and lighting. They don't look like they fit in the environment - the characters' lighting is inconsistent with the environment.

The shadows in the environment are baked, and the dynamic shadows under the characters look like fake "dark ovals" to me. Looking at gameplay for this game on youtube, they models definitely look like pre-rendered sprites.

But I'd hazard a guess and say those sprites were originally rendered from 3d models. But who knows.

Maybe they had extremly good 2D artists or they made 3D models and created sprites from these models.

I'd say the second option is what they did.

Looking at gameplay videos, I agree with phil_t.

The animations are not smooth, but are distinct steps. Most appear to be 3-6 frames, looped either end-to-end or ping-pong style.

Considering the cost of pixel art (it is far cheaper to capture 3D renders via script than to hand draw everything), I'm seconding the guess that they were 3D items rendered into sprites most likely. Sprites can be drawn with depth, in a 3D environment or a rendered environment using depth images or various types of rendering masks, which lets them move behind other objects.

It is also possible they are full 3D objects that used constrained directions and stepwise animation curves, but I think that is less likely.

That looks like some fine 2D to me. I don't think some of the fine details and the amount of particles required for the fire can be made on browsers yet given the average hardware.

But: web browsers can do 3D and it can also get pretty complicated.

Just to continue the bike-shedding , whether the characters are 2D or 3D, it appears that the large winged demon is rendered 2D without depth. On the upper portion of the right edge, the creature's left wing seems to overlap the tree which, from a perspective point of view, should be behind the tree.

[attachment=27286:without_depth.png]

The question you should ask yourself here is, "why does it matter how they rendered the graphics"?

If you are hoping to duplicate a game like this yourself, the best thing to do would be to experiment with both 2D and 3D assets for your creatures, and see which one works best.

What worked best in this game won't necessarily be the best for your game and probably wasn't best for them. They were probably restricted by time or budget constraints which probably won't affect you (or the opposite might apply, where you have no time and money and need to take the shortest route possible to completion).

Good eye!

my 2 cents:

sprites on a pre-rendered background (big bitmap style): so full 2D.

Can't recognize dynamic lights too.