Dual Blade Mechanics

I wish fatal blow and chains of hell hits wouldn't go off the screen so I could figure those out, though I'm pretty sure they're 80% since 125% seems to only apply to single-hit attacks.

You could go to the Skele Mini Dungeon or something and have a partner tell you the damages. xD

A post I read somewhere seemed to imply that Adv Dark Sight is required in order to use CoH. Is it so? If it isn't, then it would be better to not add any SP into Adv Dark Sight right? Not like it gives any advantages or anything...

The advantage is that if you manage to stay in DS after the CoH attack, you can immediately launch another instead of having to use Fatal Blow to combo out the delay.