I have not yet purchased, but have read some reviews and watched some lets play videos.

With having to roll black die (for each engaged enemy) for all actions, what is the possibilty of getting a claw? (have been unable to tell if a die has 2 or 3 of them)

Dice faces:

Black: 1 Nemesis, 3 Claw, 2 blank

White: 1 Star, 1 success*2,1 success+block, 2 success, 1 block.

Just as a follow up to this I felt like working out the expected number of successes from a white die.

You will roll a certain number of star symbols followed by one of the other results. The other result has one expected success on average (5 different results, 5 total success symbols). The number of successes from star symbols has a 1 in 6 since of being 1, a 1/36 chance of being 2, a 1/216 chance of being three and so on. Thus it can be represented as the sum of the infinite geometric series of (1/6)^r which is 6/5. Thus 2.2 is the expected number of successes for each dice.

Edit: Just noticed that 1 is included in the geometric series (I miss doing maths like this regularly and thus knowing that stuff). so in the end we end up with 1.2 (I thought my previous result seemed high).