Merc compound

In Wings of Liberty the merc compound can be built by SCVs. The merc compound trains mercenaries hired in story mode with credits. The mercenaries are hired instantly at a mineral and vespene cost, at which point that unit type is put on a cooldown timer before it can be hired again. There is a limit to how many mercenaries can be built (by type), ranging from 4 for marines to one for a battlecruiser.

Development
The structure was once called the merc haven. The merc haven used to train reapers. Training reapers worked similarly to hiring units from mercenary camps in WarCraft III. There was a maximum number of units "in stock" at any one time with that number slowly regenerating over time. Reapers were inexpensive with a build time of one or two seconds. Four reapers could be bought from a single merc haven in quick succession with another reaper becoming ready to "hire" every thirty seconds.

It unlocked reapers and upgraded s. It was removed by the beta.

In November 2008 the merc haven was removed, and the model repurposed for a bar in the StarCraft II campaign. It returned as of April 2009. Beta files list it as the "mercenary port".

Trivia
Above the old merc haven was a holographic woman doing the female night elf dance from Blizzard's World of Warcraft, itself inspired from Alizée's J'en ai Marre dance.