Does AoU still protects if...

the spirits are cast AFTER Armor of Unfeeling is cast?

Ex.
If I cast Armor of Unfeeling first, follow by Pain, would the 50% less damage and immunity from critical hits still apply to Pain or only to spirits that are up at that time?

Skill. For xx seconds, your spirits within earshot take 50% damage and are immune to critical hits.

xx seconds from casting is the duration that your little piggy's are buffed, so if one little piggy wasn't there when it was cast................

It's a little bit like a roadtrip, we leave at eight in the morning, one person shows up at nine, would he be in the car anyway ?

We as vulcans use logic Jim, Damn it Spock there is no logic in Guild Wars !
I know Jim but we have to try !

Just a quick tip, you can always test things like this by quickly rolling a PvP-Only character and hopping on over to Isle of the Nameless

Throw a spirit down in-front of the master of hammers or something and see how much damage it takes, then use your enchant and throw another down :P

Checking the wiki is always a good place to start for issues like this.

"This skill applies only to active spirits: the caster is not affected; spirits created later receive no benefit from Armor of Unfeeling. "

http://wiki.guildwars.com/wiki/Armor_of_unfeeling

Like Darth said. The buff is applied when you cast it to the spirits you have summoned at that time.

FYI, your PvE characters can use the testing facilities at the Isle of the Nameless.

However, they say that the skills are PvP versions. (I haven't tested this.)

No it doesn't.

There's a pvp version of isle of the nameless too..