AF3+2 Body: how does it work exactely?

I know you get a +X% Damage Bonus, and X = your Killer Effect, which you get from traits and can furtherly pump up with merits and gear.

What I'm wondering is if that damage boost applies to everything or only against the selected targets.
For example let's say I get +15% Killer Effect against Amorph.
Does that convert into +15% damage AGAINST AMORPH or 15% damage against everything?

You get 50% of your killer effect as both a reduction of damage taken and a boost to damage dealt. This is only applicable vs mobs you have killer effects towards: Beasts, lizards, vermin, plantoids, aquans, amorphs, and avians.

You also gain this effect all types if you have any other gear which adds killer effects. flawless ribbon and killer shortbow do this for all types. /pld, /drk, /sam, and /drg could add it for undead, arcana, demons and dragons as well. Strength will vary w/ the potency of the effect of combined job trait and gear boost.

(I have 5/5 killer effect merits and keep killer shortbow equipped for this purpose)

I see, thanks, doesn't seem that broken then, but still pretty good I suppose

Its about +8% bonus to damage reduction and damage dealt in my setup. However its only 1% for arcana, dragons, undead and demons.