Quotethat does not make me an truely skilled infiltratorYou don't say, Mr. 12' tall statue.
that does not make me an truely skilled infiltrator
... This isn't the monster-feat alternate form, - it's a racial/class SLA Alternate form. I'm not sure if that still comes with giveaways. (Being able to pretend to be a *human* paladin is subtle, by the standards of a 12ft tall angel statue)
The creature is effectively camouflaged as a creature of its new form, and gains a +10 bonus on Disguise checks if it uses this ability to create a disguise.
You may roll Knowledge (local) or Gather Information to know more about the Red Guard.