Alidar Jarok was an admiral in the Romulan military, infamous for commanding the Romulan forces in the Norkan Campaign, or what was known to the Federation as the massacre of the Norkan outposts. His home on Romulus was located near the Apnex Sea, where he lived with his wife and daughter. The experience of the birth of his child changed his character and reconsidered his views on war.
Around 2366 Jarok argued that another war with the Federation would destroy the Empire, and he became the target of a program of deliberate misinformation by the Romulan High Command, designed to test his loyalty. After dismissing him to command a distant sector, the High Command sent him false communiques, records, and orders concerning the establishment of a secret base on Nelvana III, in the Neutral Zone, in preparation for a massive invasion of Federation space.
Unwilling to allow a war that would devastate both sides, Jarok stole a Romulan scout ship and crossed the Neutral Zone, seeking refuge aboard the USS Enterprise-D. Claiming himself to be "Sublieutenant Setal," he informed Captain Jean-Luc Picard of the offensive. However, Picard was skeptical, given Jarok's reluctance to reveal any Romulan military intelligence beyond the buildup at Nelvana III, which included the self-destruction of his ship. Only after Jarok revealed his true identity and provided the disposition of the Romulan fleet along the Neutral Zone, did Picard order the Enterprise-D to Nelvana III.
When the Enterprise-D reached Nelvana III, they found no evidence of a base whatsoever – only a probe designed to send out a subspace signal and ionization disturbances. Realizing that they had fallen into a trap, the Enterprise-D attempted to retreat, only to be surrounded by two Romulan warbirds commanded by Tomalak. Tomalak revealed the deception, and announced his intention to take the Enterprise-D back to Romulus as a trophy.
Fortunately, Picard had planned ahead and arranged for substantial Klingon forces to follow them under cloak. Suddenly finding himself outgunned, Tomalak withdrew. Jarok, realizing that he had sacrificed everything for nothing, committed suicide by ingesting a felodesine chip. He left only a letter for his family, and the memory of his courage. (TNG: "The Defector")
Alidar Jarok was played by James Sloyan.
Picard has traveled to Romulus as part of a Federation-Tal Shiar intelligence conference, convened after the Romulans enter the Dominion War (in In the Pale Moonlight (episode)). The story takes place approximately eight years after the events of "The Defector (episode)."
In the story, Jarok's wife is named Ai'lara and his daughter is named Tiaru, aged 10-12 at the time of Picard's visit. His note takes the form of a video recording, sending his love to his family and warning his daughter against the evils of paranoia and militarism, that have already damaged the Romulan Empire so much. He also stuns them by revealing that they have been under the secret protection of General Koval, one of Jarok's sympathizers within the Tal Shiar. The message also gives Picard the secret codes needed to reactivate Koval as an agent for Federation Intelligence. After leaving the Jarok residence, Picard signals Will Riker in the capital city, and is pleasantly surprised to learn that Koval is now the head of the entire Tal Shiar.
Alidar's daughter, named Tiaru Jarok in that short story, is prominently featured in the computer game Star Trek Online. Taking place in 2409, she is depicted as commander of the R.R.W. Lleiset, the flag ship of the "Romulan Republic", a break-away faction led by unificationist D'Tan.