Wall of Elements is a skill located in the Destruction Staff (which can be found in the Weapon skill tree). Wall of Elements is a base skill, and can be morphed into Unstable Wall of Elements
or Elemental Blockade
Wall of Elements deals the following types of damage: Flame Damage, Frost Damage, Shock Damage. Which means that it gets buffed by the following blue champion point trees: Elemental Expert, Elf Born, Spell Erosion, Thaumaturge. Also the following red champion point trees protect against this skill: Elemental Defender, Thick Skinned.