The Tsoo are an Asian gang that operates in Paragon City in the City of Heroes MMO. They employ ancient mystical secrets from varing cultures in China, Japan, and Korea.
The Tsoo are also linked to the "Facemakers" organization in the Rogue Isles. Not only do they steal designs and material from the Icon stores in Steel Canyon and Independence Port, but they also supply the sweatshop labor that are then employed to create the knockoff outfits and accessories, which they then transport through the Marcone Family to then sell at Facemakers.
(See their Paragon Wiki entry for more information.)