The Roach was designed as a tank unit for the Zerg, one that provides supportive fire as well. This is very obvious due to the immense amount of hit point regeneration the beast has, but he regenerates fast only while burrowed. It has mostly taken over the role of the Hydralisk in the original Starcraft concerning ground units in most cases. It is durable, but has rather short range and a low damage per second. It has become exceedingly popular in Zerg vs Zerg match-ups, according to Blizzard, because of it's extra damage to biological units.
