This is a very cool game man. Did you make this all by yourself, if I may ask?
Clawmage:First I'll say a few words about my experience as the clawmage. I lost at level 6, on easy. Now, I never tried the death chain ability, so maybe that was where his power lies, but using the other abilities I was powerless. The meteor strikes just weren't enough damage I guess. And the timestop just wasn't long enough. I dunno, do what you will with that bit of info.
The Vampiress: I love how her glow changes from night and day. If drain essence is temporary, could you get the bonuses to show in yellow? And perhaps some kind of effect like dispel or disenchant. As it is, I can't tell anything happens unless I carefully watch my stats...and sometimes when I did that, I didn't notice a change. Also, is increased range the best thing to increase for this ability? By level 20 of the game, I had about 400 for agil and str, and like 600ish for intel. Drain essence added 3 or 4 to each stat(I think) which was minscule by those standards. If it is not as effective late-game that is perfectly fine too--just sharing what I noticed.
Field of the fallen: Freakin' cool. When I saw this for the first time I almost ished my pants. Very well done effect. Maybe play out the banshee sound effect a tad more, and maybe a tad more often. The last levels of it maybe lasted a tad long
The Sun Warrior: I loved this guy! What a cool model and immolation effect. The whole power of the sun thing is really unique too. I noticed a few grammatical...not mistakes, but...well grammatical fixer-uppers

For burning skin, I suggest you put: ...so much that he became immune to fire and he can just let his skin burn. For the cactus, the word its doesn't get an aprostrophe for posession. "It's" is only for "it is". Something belonging to "it" is just "its". Makes no sense I know. For sunbeam, change heat to hot.
A suggestion for the sun abilities. Maybe an additional sound effect when the beams strike the enemies. Something like the brewmaster's ultimate. Something that gives the sense of heat, or explosion, or impact. But I wouldn't remove the current sound, it is also good. And I also wouldn't make it something so overpowering like a building explosion. Just something to show some damage happening to the enemies.
When I cast sunrays, the sun warrior paused for maybe two seconds afterward. It is because the casting time is a bit too long. This took time away for me to attack while the enemies were stunned. Also, the stun didn't always work but it worked 90% of the time.
Great Work! I wish I were better at this stuff because I'd love to offer to help you with this. But alas, I am a mere noob.