The security and intelligence service of the Vulcan government, to which the mercenary Tallera falsely claimed to belong while hunting the pieces of the ancient psionic weapon called the Stone of Gol.
The V'Shar is Vulcan's security agency, mentioned in The Next Generation two-part story Gambit. Aboard the mercenary ship of Arctus Baran, the Romulan-looking crew member Tallera confides to Picard that she is really T'Paal, a V'Shar operative sent to stop Vulcan isolationists from reassembling the Stone of Gol.
The claim is a lie. When the Enterprise checks with Vulcan, Security Minister Satok knows of no such agent, and T'Paal turns out to be a member of the isolationist movement herself, using the mercenaries to gather the fragments.
Her plan fails on Vulcan when Picard realises that the resonator has no power over minds free of violent thoughts.