Poison Injection is a skill located in the Bow (which can be found in the Weapon skill tree). Poison Injection is a morph of
Poison Arrow.
Poison Injection deals the following types of damage: Poison Damage. Which means that it gets buffed by the following blue champion point trees: Master at Arms, Mighty, Piercing, Precise Strikes, Thaumaturge. Also the following red champion point trees protect against this skill: Hardy, Iron Clad, Thick Skinned.
ESO Skillbook