Roach

The Roach is a Zerg ground unit set to appear in StarCraft II.

Overview
The Roach is a particularly tough Zerg breed due to its high speed regeneration ability.

Regeneration
One-on-one, a Roach will generally win in a fight against its enemies, as it regenerates 15 HP per second (25 hp/second with Organic Carapace). A Roach can heal fast enough to retain approximately 50% of its hit points if hit by a Psi Storm, and over 80% of its hit points after its regeneration has been upgraded.

Attacks
Currently, the Roach is a ranged unit, giving it added utility at choke points. It has possessed the ability of attacking both air and ground units, though is currently ground only.

Strategies
A roach's regeneration is quite powerful, and it can often regenerate faster than it takes damage.

Roaches work well in small skirmishes rather than large encounters, because they are vulnerable to focus fire. A single Roach can defeat a single Stalker due to its high regeneration, for instance, but five Stalkers can defeat five Roaches with focus fire. Groups of Marines can counter Roaches as well.

Roaches are also vulnerable to sustained damage. Roaches are strong against opponents that attack slowly and do low damage per attack, such as Zealots. Karune reports that "in theorycrafting, they seem stronger than they actually are, although specific units must be used to counter them, or additional micromanagement time be taken to defeat them. Siege Tanks, Stim Packed Marines, Stalkers, Immortals, Dark Templars, Hydralisks, and any air to ground unit, are all effective at killing Roaches with a little micromanagement."

Zerg vs Zerg
Roaches and zerglings are used early in zerg vs zerg matches. Compared to zerglings, roaches are a more defensive unit. Cost for cost, roaches win against zerglings in chokes but lose in open areas. Later in the game, numerous roaches can defeat numerous zerglings even in open areas.

As a game progresses, a roach/hydralisk combo can defeat a zergling/mutalisk combo.

Development
As of May 2008, due to a bug Roaches are not affected by the Dark Swarm's secondary ability of preventing units inside it from firing. Dark Swarm was later removed from the game by October 2008.