Energy shields are the ugly duckling of the Armored Core series; From one of the franchise’s most useless pieces of gear, they have evolved into an essential component that is literally part of every AC you fly.
When they first made their appearance in AC, EN shields weren’t quite as effective as we all hoped they would be. While their defense boost did turn your AC into a brick wall, their energy drain and weight ensured you also had just as much mobility as one.