A light rocket Kbot used mainly to push the front-line towards opponent's base. It can out range light laser turrets so if your enemy expands solely with a Commander, Rockos can force him to retreat. In bigger numbers and with repairing support of resurrection Kbots they are able to take down more advanced defensive structures.
To protect them use your Commander / Constructors to build progressing defense. In comparison to their RED counterpart Storm that are a bit faster, but weaker at the same time.