I feel like the shading needs to be more intense, like around the necks, or in the background (given that it is basically just a line separating two colors). The anatomy is good, but in order to make it shine you would need to work more on the that.
I'm not sure blue lining works well on Yeelon's skull and besides, it would seem like Kelzad is brighter when they both should shine the same, IF Yeelon is actually getting electrocuted.
The background seems a bit boring. It definetively would have been better if the city was there, with a magenta glow coming out of it, to set the mood a little.
Great work on the skull anatomy though, really cool! On the other hand I think the electricity on Kelzad's head is way too round and inconsistent, as opposed to the typical look for it wich is quite straight, and thinner.
I think that's all I have to say about it.
Don't get me wrong I like this piece, and hope this review can help you improve you future work!
Godspeed.