if im not wrong (just quoting what iv read earlier) these dont work at all / "that well" or not the way we are expecting them to work.

Iv heard the dmg reduction one reduces dmg done when one of your ninjas is under chaos (blah if thats true) never botherd testing that out myself. but i havent testet out the atk/nin pen myself but just guessing on how "little" power they give compared to the others, they shouldnt be prioritized over HP/Att/Def/Nin/Crit/Combo/Inj/Init. They do give a powerboost, so it does have some effect we just (or i) dont know that yet. Had a red one of one of the pen one and it gave nice boost but i didnt see any "big" difference tbh.