The Most Merciful Thing (OOC)

[lostsole31]

He looks human in all ways save his thick skin (which you detect more through tactile than looks, his incredibly thick and sharp claws, and a dichotomy between intellect and knowledge and a very bestial undertone). In short, he is some manner of augmented human.

Anyone with Knowledge (nature) or a bardic knowledge check can roll a DC 15 can roll it to figure it out ...

And you can make a Knowledge check untrained (basically an INT check) only if the DC of the subject matter is 10 or less. The standard PHB pantheon - names and basic portfolios, but little else - should definitely be common enough to do that.