Command massive armies of tough space marines or nightmarish cyborgs in endless battles across the Strogg home planet.
The female flight crew of the destroyed Patton-class destroyer, U.S.S. Rommel, equipped with blasters. You heard the voices of such pilots in Quake 4, but they never showed up to the battles in person.
They will seek out other survivors of the massive downed ship and fight a desperate battle at the crash site until heavy Marine reinforcements arrive. They will be out for revenge against the squibs at the air defense cannons, too.
In version 4, female marines will speak with their voices from Quake 4, albeit only saying little.