Deflect Arrows question:

[What's in the box?]

The feat benefit says: You must have at least one hand free (holding nothing) to use this feat. Once per round when you would normally be hit with an attack from a ranged weapon, you may deflect it so that you take no damage from it. You must be aware of the attack and not flat-footed. Attempting to deflect a ranged attack doesn't count as an action. Unusually massive ranged weapons (such as boulders or ballista bolts) and ranged attacks generated by natural attacks or spell effects can't be deflected.

The last part: natural attacks, what would be categorized by this? Like a manticore's spike seems like it would be a natural attack that is ranged? What about a Soul Knife who throws their weapon at you? Alchemists fire? Alchemist bombs?

Trying to get a better feel of precisely what this feat allows the deflection of: Arrows and bullets I get but I don't see a huge difference between an Arrow and a Manticore spike? And why NOT a spell like Acid Arrow?

[Aydin D'Ampfer]

Natural Weapons are a specific class of weapons. Manticore Spike, Camel Spit, and a slew of others qualify. Alchemist's Fire, Soul Knife, and Alchemist's Bombs are not some of these.

Basically, Deflect Arrows allows the defection of anything that comes from a manufactured weapon. From a 'real-world' perspective, its a matter of training. Its easy to train arrows getting shot at you, less easy to train a manticore attacking you.