Lovok (Changeling)
The impostor Colonel Lovok was a Changeling and Founder of the Dominion. In 2371, this Changeling replaced the Romulan Tal Shiar officer known by the same name. 

When Enabran Tain, the former head of the Obsidian Order, proposed an alliance between the two intelligence groups to destroy the , this Changeling posing as Lovok saw a great opportunity. The Founders were aware that the two groups were ruthless and efficient organizations that posed a great threat to them. By doing everything possible to push this alliance, they effectively led the two groups into a trap that would reduce their capabilities. 

Lovok, commanding a Warbird, took Tain on his ship to command the combined fleet for the Battle of the Omarion Nebula. When coming across Odo and Elim Garak, he ordered them taken aboard as Tain wished. He allowed Garak to work for Tain, but barred him access from any critical system. He took Odo prisoner and allowed Garak to interrogate him. After Garak reported no new information from him, and the recommendation that Odo not be killed, Lovok agreed with him and stated his usefulness in gaining more information about Changeling abilities. However, he later challenged Garak, stating he observed that Garak was protecting Odo with a personal interest. Garak denied it, and Lovok said he would be watching him.

When the Warbird sustained heavy damage, Lovok left the bridge and helped Odo and Elim Garak to escape, stating "Because no Changeling has ever harmed another." He gave Odo another chance to come with him to stay with his people, but Odo declined. He was promptly transported away. ()

de:Lovok (Gründer)
Changelings