Apparently there's been another name change and it's now called "Raven"
Defensive Drone: With this drone you are able to intercept enemy projectiles, e.g. rockets of the terran missile turrets. Therefore this special weapon is especially well suited for attacks on bases. Against small bore (like the spines of the Hydralisk), however, it is powerless.
Plasma Surge: This ability is similar to the shield battery in sc1 as it allows the ht to recharge the damaged shields of all friendly protoss units in a selected area