The Reaver is the Protoss longe range unit. The Reaver first manufactures the weapons, Scarabs, at fifteen minerals units a Scarab. Then it fires the Scarabs which go o their target and upon contact they explode. Yes it does make you pay for the Scarabs but it's worth it. for example, if you fire a Scrarab at a group of Zerglings and they are all grouped together than all of them will die. The Reaver does have one major flaw though, it can't fire at air people so a Reaver group of Reavers escorted by a group of Scouts can make a very deadly combination. I mainly use Reavers as a first line of both offense or defense but mainly offense because the Reaver can destroy defenseive buildings like Sunken colonies without being hit. I strongly suggest that you always upgrade Scarab capacity before you take a reaver into battle or you may find yourself in dire straights indeed..
