Vkruk was a Reman male who served as the Reman Viceroy to Praetor Shinzon in 2379. In the 2350s, Vkruk worked in the mines on Remus along with the rest of his people, under the boot of the Romulan Star Empire. When the young Shinzon was deposited into the mines, Vkruk took it upon himself to protect the boy from the other Remans and Romulan guards.
In 2379, Shinzon had risen to become Praetor of the Romulan Star Empire, and Vkruk served as his Viceroy and second-in-command of the Empire. He also stood at Shinzon's side when they attempted to take the Scimitar into Federation space and attack Earth with a Thalaron weapon. Vkruk relayed orders to the crew, monitored Shinzon's deterioating health, and assisted Shinzon in the telepathic rape of Deanna Troi.
In the final showdown with the USS Enterprise-E, Vkruk led a boarding party aboard the Enterprise in order to find Captain Jean-Luc Picard and bring him to Shinzon so that a blood transfusion could save his life. He was prevented from doing so by Commander William T. Riker, and later died in battle with Riker. (TNG movie & novelization: Star Trek Nemesis)
In an alternate reality, Vkruk staged a coup d'etat in the Romulan Star Empire in 2379, usurping the position of Praetor. He was responsible for the death of the US Enterprise's first officer Commander Data. (TNG novel: Q & A)