DRK Defensive CD's. Am I missing something?

[Absimiliard]

Yea I was wondering about this as well. Glad people explained it.

BTW how exactly does TBN work?

It gives you (or someone else you use it on) an absorb shield for 25% of your/their maximum health at the cost of 3,000 MP. Other forms of mitigation are taken into consideration before TBN's shield; rampart, shadow wall, or what have you will all reduce the amount of damage the shield itself takes.