Introducing!

"Tempered by hardship and strife, the resourceful terrans have proven a formidable match even for the technologically advanced protoss or the ravenous zerg".

Terran is a Human race in the starcraft serie. They was the mainrace in Starcraft 2: Wing of liberty. In Starcraft 2 you play as Terran in the campaign.

According to Dustin Browder, the terrans have "enough stuff already" and as such, it is difficult to know what to do with them. Terrans are more flexible in multiplayer than the zerg or protoss and the team doesn't want to add units/unit properties that increase this trend. Still, Blizzard is planning on de-nerfing the reaper. Reapers will gain an out-of-combat regeneration ability called Combat Drugs.^[
At BlizzCon 2011, three new terran units were revealed—the warhound, the shredder and the hellbat. Notable changes will be made to the battlecruiser as well. However, the shredder was later removed. Overall, the new terran theme for Heart of the Swarm is a mech one, standing in contrast to Wings of Liberty which was more balanced around biological terran units.
As of June 2012, the widow mine, which could attack both air and ground units, was introduced.
As of September 2012, during the beta, the warhound was removed.
A general theme for terran units in the expansion is that they are more high-tech than units in previous installments.