User blog comment:PsijicThief/A New Guild/@comment-24049985-20131014131857/@comment-8248675-20131014182107

Summerset Shadows is what you mean and indeed it doesn't count. It's a rival thieves organization, which is blamed for killing their marks (Even though it is not true, they just rob those that already dead, which makes it not much better). And all you can do, is to eliminate them, oh and don't forget to burn their banner to send them a clear message. Also, it is more then just a side quest. It's more of a major job that you have to do in Winhelm, to give Thives' Guild a foothold in Eastmarch and Windhelm. Smaller jobs that you do in each city would be more like side guests. This is one job that puts you one step closer to completing Thives quest line and getting the achivement, "One with the Shadows".