About Penetrating Strike

[CrystalIce]

So penetrating strike says has a requirement for Shifter Griffonheart level 12 so what I wanted to know is if Ulbrig is the only non-fighter allowed to use penetrating strike? And if so, why does pen strike appear as a magus bonus feat for Magus Eldritch Archer?

[Drake]

Penetrating strike is a fighter feat. Ulbrig archetype gives him access to the feat (like it can happen with other archetypes, like battle oracle and battle shaman getting some fighter only feats).
In the case of the eldritch archer, it's not eldritch archer per se, but the magus class.
Magus class gets fighter training at lv 10, so they count has fighter (2 lv of magus counts for 1 level of fighter) for the prereq of feats. So if you mix fighter (or eldritch knight) and magus (like 10 magus+ 7 fighter or 7 eldritch knight), you can technically reach the lv 12 req. for penetrating strike when choosing a magus bonus feat.