A Romulan D'deridex-class warbird of the Tal Shiar, part of the joint fleet with the Obsidian Order that was ambushed and destroyed by the Dominion in the Omarion Nebula in 2371.
The Belak appears in the Deep Space Nine episode The Die Is Cast. It is one of the twenty cloaked Romulan and Cardassian ships that Enabran Tain and Colonel Lovok lead into the Gamma Quadrant to destroy the Founders' homeworld from orbit.
The fleet bombards the planet only to find that the life signs were faked and the world abandoned. A hundred and fifty Jem'Hadar ships then come out of the nebula. The Belak is among the first to suffer, losing main power early in the fight before it is destroyed. Lovok turns out to be a changeling who encouraged the plan so that the Dominion could wipe out both intelligence services in a single battle. Garak and Odo escape in a runabout with the Defiant's help.