Ok, say you have Smokey Feet Captain America. His defense is perplexed by 2 by Doc Strange. Then say, another character perplexes his defense by one more giving him a 21 defense. Would the following also continue to increase his defensive value? Now 21 perplexed defense SF Cap steps into hindering terran, (Plus 1) = 22 defense, and he's not targeted by a range attack kicking in his engeryshield deflection (plus 2) = a total of 24 defense.

Would Cap indeed have a total defense of 24 under these situations?

No Captain America's defense Caps at 21.

Nope. Rule of 3 applies to all modifiers, of which perplex, ES/D and the hindering terrain bonus all are. Now, your perplexing Cap's DV up still gives him a 21 from close combat as well, so if you see some big bruiser coming in, it isn't wasteful.

Yup yup. Rule of three is all and controls all. There is no denying the rule of three. If you add 3 to any number in clicks, stop. Nothing else matters. The only and I mean ONLY exeption to this is a critical hit.

Critical hits are not actually an exception. The Rule of 3 applies to combat values. Critical hits modify damage dealt. These are two separate things. Since critical hits modify damage dealt, they are not subject to the Rule of 3.

Just stick Pym Particles on him and select the +1 def, now it's a permanent +3 on range all the time.

Not quite the only exception.

Critical hits are an exception because they add to the damage dealt. The rule of three applies to combat values. Damage is a combat value, damage dealt is not. Damage dealt is something that occurs during an attack.

There are other things in the game that modify damage dealt. Green Arrow's "Hail of Arrows" special power is one. Floronic Man's "In Touch with the Green" is another. The Mail Box and Soda Machine objects bring this up fairly often.

The real exception is minus modifiers....

+4 and -1 dont interfere with the rule of 3 and you still get the full +3.
(lets say somebody tries to perplex down his defense)

Or if someone already perplexed down his defense you could perplex it up by 4 and get +3

Add up all the plusses that he has, and then subtract all the minuses, and whatever number that ends up being, he can only have a total of three added or subtracted from the printed value.

Note that replacement values are different animals, but the OP gave no replacement values.

I'm still not sure on how 'replace then modify' really works.

If Dr. Strange is using Defend to replace Wolverine's 16 Defense value with 18, and Deadpool has LOF to Wolverine only, can Deadpool Perplex Wolverine's DV up another 18? I don't think he can (he'd perplex it up to 17, but not 18) but just wanted to check.

If Deadpool used perplex on Wolverine his defense would be a 19.

It just changed in Blackest Night. There's no timing rules anymore, it's ALWAYS replace than modify. So, say your movement is halved (Replacement) via say, Charge and then you Perplex it by +3. Standard 8 move charge gets halved to 4, then upped +3 to 7. Neat way to catch your opponent off guard

holy crud... i really need to actually read the new rulebook rather then just buying the starter for the figures. I didn't know this one but it'll be most helpful.

Of course, for calculating the speed value the rules indicate that you replace then modify so that the movement during the Charge will be 7, the actual act of Perplexing must be done before the Charge action. (It will still be 7, but make sure to Perplex before you Charge.)