DRK feels weak

[pastry777]

If hit points aren't mitigation, then temporary hit points aren't either. TBN mitigates exactly 0%.

I'll requote myself:

"Mitigation = Incoming damage reduction
Mitigation =/= Self-Sustain"

TBN actually soaks damage before the rest of the damage applies to your HP. Temporarily changing your maximum HP doesn't "mitigate" or "reduce" the incoming damage inflicted to your HP.