@Diablofire: Just load the last autosave and visit the respec demon, if you want to verify it, but this is the main reason why the Tenebrium skill is discussed so much here.
I was just surprised by your numbers, because I thought that you have figured out that the weapon skill actually will matter and only the displayed damage on the paper doll is wrong, which would put an end to all the complaining.

If the damage boni of abilities would stack, I would expect them to work the same way as the health boni do, namely additive not multiplicative. With the -25% health penalty on hard, Glass Cannon reduces your life to 25% (100%-25%-50%) of the value based on your CON, not 37.5% (75%*50%).

Last edited by eidolon; 28/07/14 08:15 PM.