Changeling who infiltrated the Romulan Tal Shiar and lured a joint Romulan and Cardassian fleet into a Dominion trap.
Lovok appears to be a colonel of the Tal Shiar, the Romulan intelligence service, who joins Enabran Tain in a combined Tal Shiar and Obsidian Order strike against the Founders' homeworld. In reality he is a Changeling who has infiltrated the Romulan command.
In The Die Is Cast, after the fleet is drawn into a Jem'Hadar ambush and destroyed, Lovok reveals his true nature to Odo. The entire operation was a trap designed to wipe out both intelligence services. He urges Odo to rejoin the Great Link and allows him and Elim Garak to escape.