Looks like the Sisters of Battle will be the 2nd race for the Sisters of Battle expansion.
There’s a ton of info in the article over at gamespot, including this bit about achievements.
Finally, Soulstorm will introduce achievements, which will help reward longtime players online, though these are not Games for Windows – Live achievements. Dawn of War is a popular multiplayer game thanks to the fact that it lets you take all those incredibly elaborate, detailed units online to crush other players. Each faction will have its own unique achievements, such as Force Commander, which is rewarded if you win 25 ranked games with the Space Marines. Or there are general achievements, like Hot Streak, which you get if you win 10 online matches in a row. These new achievements should help fuel the competitive fires in terms of multiplayer.
That’s the third expansion… THIRD! Nine races in multiplayer. Freakin’ NINE! The campaign takes place on 4 planets and 3 moons! I’m actually quite excited for this!
(Spotted on www.evilavatar.com)