A long time ago, The great beings invented a robot capible of being a guard. Then about 100,000 years later the Makuta got their claws on the Battle unit. It was used to protect in raids and fight wars. But they ran into a problem instantly. Their armour wasnt very thick. Most units were taken down with on shot. Most wepons including Tearox's Venom talon, Xarana's Trident, Scarecrow's edged blade, and Esorot's lIGHT BLADE would also do the job of slicing them in half of cutting anything else off. Then the Makuta forced the matoran to make a heavyer unit. Both units are in battle.