Warforged Juggernaut's Level 20 Daily Power is Crag of Steel; a stance that gives you a bunch of stuff, but the part of the power I'm interested in here is:
"Until the stance ends, you gain resist 5 to all damage, and whenever this reduces an attack's damage to 0, you also negate that attack's effect on you."
The way I'm reading this, in order for this to kick in: an attack must do damage, which must be less than 5, AND also deal an effect.
An attack that just deals an effect isn't ignored because the stance doesn't "reduce the attack's damage to 0" - it already was 0 (or rather, there was no damage/null/etc.)
I can't envision any other way of triggering the text in question;
- Resistance doesn't stack.
- If a different resistance is higher and negates the attack it doesn't count because it's "whenever THIS [Resist 5] reduces an attack".
- Temporary hit points are just me taking the damage somewhere else...
At best, I can see it synergising with a handful of specific powers that otherwise reduce attack damage by mechanics other than resist, but those are few and far between (and generally reduce the damage by a not significant enough amount to negate 90% of a reasonable opponent's damage.)(And my party hasn't picked any of the dozen specific paragon paths/backgrounds that get them.)
Overall, this means, I can't really see an occasion where this text would actually kick in. It's good for negating level 1 creature's attack effects if they happen to roll a 1 on their damage dice... as a level 20 Daily.
(Don't get me wrong, the rest of the power is fine. Resist 5 is fine. Free damage is good. Resist forced movement is good. It's just an unlikely enough confluence of events for that power to trigger that.. it feels like I'm missing something?)
TL;DR: Am I mis-reading this part of the Crag of Steel power or is it just not going to come up in normal level-appropriate fights?