Ok, since this piece was introduced to me from a friend here on dA I had a look at it and figured since you were accepting critiques I would give you one.

Vision: I ranked this the highest because a viewer can tell you had a visionary idea for what you wanted to portray here. However, although there is a visionary statement it's hard to tell due to the slightly lack of emotional mediation between the two characters.
The expressions are unclear.
What I get from this, and I may be wrong, is that the black wolf appears remorseful for his actions and the white wolf appears to be begging for pity or an end to their fight/battle.
If this isn't what this scene is meant to portray, then perhaps it's time to study a bit about basic emotions and how to portray them properly.
The visual stimulation of this image is pleasing. The lighting and shadows are actually very well done, and I do like the idea of having multiple light sources. It gives a nice 'natural' feel to the image making it pleasing to the eyes.
However it's the lack of emotional portrayal that drops the impact just a tad.

Originality: Although there's quite a few 'dark vs light' or 'good vs evil' images out there, this one holds a unique candle among them. It's not a terribly typical scene so in that right it has some originality to it.
The setting also ads a nice touch to the originality aspect. The towering gothic type background structure and almost fantastical atmosphere really brings a sense of 'other worldly' materialization to this.

Technique: Ok, this is kind of where it gets a bit dark, but bear with me, I won't just pick on your technique as there are areas here that you did very well.
The lighting and coloring technique you have here is effective. Slightly choppy and more 'speedy' but effective. The furring is overall good, but it is a tad 'sloppy' in certain areas which leaves it appear to be rushed.
The lighting and shadows are pretty well placed, and the back lighting is done well. It's not too bright but not too faint.
I like how certain areas are sharp while others are softer, adding a nice sense of depth.
There is one big area that I find displeasing on the eyes, and that is the blood. It appears to be VERY red and bright when in reality it should be darker and less 'vivid' in color. Blood isn't actually that red when it comes out as it coagulates pretty quickly once air hits it.
Also, I'm not quite sure where these wounds come from. I can see the blood on the hands being from gripping the sword, but the wounds on the upper arms/biceps?
It's hard to understand in this position how those wounds got there.
The anatomy on this is not bad, a bit wonky in some places but not overwhelmingly bad. The tails on both characters (which I assume to be wolves) are a bit long, but that could be for aesthetic purposes, or perhaps style reasons.
The ears on the black wolf character are a bit low set on the head, and being pulled back they give a very 'submissive' feeling rather than power or even dominating, which would be the appropriate expression to portray here seeing as he is the one standing. The white wolf character's expression is rather well played. It echoes defeat and submission.
As it has been said, the hands could use a bit of work, but it's not a huge problem.
The broadsword is done fairly well too, the shine and the texture depths are well played, however the perspective is a tad off. Nothing major though.
The fabrics and cloth are done well. A bit drab compared to the other texturing done here, but it's decent enough to give a general idea.
Overall, with a few minor errors aside, this image is pretty well done as far as technique goes. A few things to work on in the future, but nothing major.

Impact: The image does have an impact. The atmosphere and dramatic lighting help bring a sense of desperation as well as finality to it. Like a confrontation being addressed in an immediate sense.
The posing is well done and the background as well.
As said, aside from a few anatomical errors this image holds a nice impact, despite lacking a more emotional stimulation.
I enjoy this piece

Figured I'd write a critique of my own because both of the others had good points about it, but I think that they were a bit unfair with it.

First thing I noticed that was a bit distracting was how the fur was very crisp and detailed near the face/neck areas, but became very loose and undefined as it because lower, especially on the tails. I haven't had the chance to check out your gallery and compare it to anything else as far as that. The fur itself is very nice, though, I just wish there was a bit more consistency in the overall fur technique. The other thing is, I couldn't help noticing how the grey/black wolf looks as though he is distracted, which I feel took away from the general impact. I really do like the overall idea and concept, but I think there are some things that could have been fixed to execute it a bit better. I can definitely say that I believe you should work a bit on your facial expressions. But not so much on the white wolf, I can't help but think the grey wolf could use a bit more work in that. Overall, I think you did a nice job on it. I really don't see what all the fuss and negativity is about in the comments.
Really, your anatomy is pretty well rounded, but we all have our flaws and could always use some more help. You definitely are very skilled and talented as far as painting like this goes. I can tell from the few things I've seen that you are indeed a very talented artist, and I will definitely say that I envy you. I really like the stances and such, aside from the grey wolf's facial area. I really do believe you should get a bit more credit and praise for the good things about this piece. I really like the contrast between the white wolf and the blood, although I think (and I mean this in absolutely no offense) that the sword looks a bit... well, childish is the best word I can think of. Perhaps maybe you could find a sword with the golden hilt and such that you could reference from. Maybe something like this; [link] (Of course that decision would be up to you)
I really do think the idea in general for this is on the fence about creativity, but I think you put enough of your own spin on it. Maybe a different perspective/angle on this would change the impact a bit, but I personally believe it could be the expressions. (But then again, I'm the type of artist who believes that expressions tell a lot about a piece)

In summary, I believe you did well on this, and your vision of it was definitely very good, but I think it could be executed a bit better.
(I haven't written a critique in a while so I apologize if I sound like a rambling moron )