- By definition "Virtual Feats" are abilities that mimic Feats for the purpose of gaining Feats that require Prerequisite Feats.
- Aegis have a customization option called "Harden Strike" that function much like the feat Improved Unarmed Strikes with the additional bonus option of your choice to using Slashing and Piercing damage types besides Bludgeoning with unarmed attacks.
- Can you then choose to take Greater Unarmed Strike feat with the Aegis' Astral Suit's Hardened Strikes option as said Virtual Feat?
- Now it's been a while since I last checked, but I remember reading that if you have feat "y" that has a prerequisite feat "x" and that said prerequisite feat "x" is unaccessible for a time; then the feat "y" can't function till feat "x" is accessible.
- With that out if the way. Can I then have a scenario like this, where an Aegis can't use Greater Unarmed Strike feat until such time as he forms his Astral Suit where it's opted to have Hardened Strikes?
RAW, hardened strikes make no mention of Improved Unarmed Strike in any capacity, and Greater Unarmed Strike does not mention hardened strike as any kind of alternative requirement. So there is no interaction between the two and hardened strikes does not help you take Greater Unarmed Strike in any way.
Moreover, Jeremy Smith (one of the co-founders of Dreamscarred Press and an author of the aegis) confirms that this was intentional, precisely to avoid the situation where you use it to meet a prerequisite and then swap it out.
On the other hand, it is not terribly unusual under the rules to lose a prerequisite, and there are rules for handling it—you simply cannot use a feat you have if you have lost any of its prereqs (see this question). So it’s a reasonable houserule to allow an aegis to take Greater Unarmed Strike, and just have that feat stop functioning if they swap out hardened strike. I’d certainly allow it—better to lock you into a particular customization, or to allow you to temporarily go without a feat, than to force you to burn a feat on an entirely-redundant prereq. Jeremy does caution that this wasn’t tested, however.