@LaughingWolf : Armor is what it's always been, the armor you wear and it directly effects how much damage you take per hit. I'm not sure if it's direct DR or armor converted into a percent but I'm mildly sure it's converted into a percent. Hopefully a static calculation and not something that alters with level because thats stupid, and dumb, and crap so... i hate when games do that. I mean it's already a percent, just make low lvl armor be like 20-30 and high lvl armor be 50-80...not that hard, no need to make it get crappier blah blah /rant.
Guard is temporary health (no duration, stays till it gets dmged away). It's speculated (and probably right) that your max guard is the same as your max life. Guard is, just like health, effected by your armor so the 200% armor bonus for 10 seconds from War Cry upgrade will mean the guard you gain from it will ultimately last longer. Also that 25% bonus guard seems like it means you'll be able to have Guard reach out 25% more then your max HP would otherwise allow.
For tanking your gonna want a lot of armor, and a means or 3 to generate guard effectively and often. Think of it like a preemptive heal that's not really healing you.
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Tripple Ninja'ed!