Killer Effects

I've been away from the game for a while and I was surprised to see a few posts suggest some Enhances "Killer Effects" for BST dd gear. I couldn't find any threads on this and there was no listed damage increase on the wiki. Can someone please explain this?

I would assume that's in reference to this http://wiki.bluegartr.com/bg/Ferine_Gausape_Plus_2

"Gives about 50% of your Killer Effects as a Damage Boost and Damage Taken reduction
+5% Damage and -4% Damage Taken with normal traits. "

Although, that's only against the appropriate family for said killer effect.

Would be particularly nice stacked with killer instinct.

Thanks for the link! Making a lot more sense now. Does anyone know how much Monster Helm +2 equates to in terms of damage? Are there situations where this is viable for TP set?

Since Monster Helm +2 is 5% Killer Effect, you would get half of that as a damage boost while wearing Ferine Gausape +2. You wouldn't use this for TP phase, but perhaps for Primal Rend/Cloudsplitter, or while brewing an NM that falls under one of the 7 monster families for which we have a killer trait.