Pentaaro is the main villain of the Star Trek Online episode, "Mirrors and Smoke" - he is of the Kentari race, who were divided into two camps of thought in regards to ancient practices regarding the Lukari and alien races : at first he appeared a gruff but loyal follower of the Prime Minister but would quickly shed this guise and reveal himself one of the commanders of the terroristic Traditionalist group.
Pentaaro is introduced as a high-ranking military figure under the command of the Prime Minister, he is unfriendly and untrusting of both Lukari and alien "outsiders" but seemed to obey the whim of his commander, he also claimed to be doing what he saw as best for his people and planet.
However, after the Kentari moon was devastated by a protobomb assault by the Tzenkethi he openly betrayed his commander and attacked the Federation directly, revealing that he was behind several Traditionalist assaults on the visiting Federation team and an attempt to sabotague the Federation's efforts to revive the dead moon and ensure the Kentari would keep their food supplies.
Blinded by genocidal hatred for the Lukari and any that defended them Pentaaro declared that the previous exile of the Lukari was not sufficient and that the Kentari should of wiped them out instead - he then engaged in a brutal space-battle alongside a squad of loyal Traditionalists but was opposed by both the Federation party and Kentari who did not share his brutal views on the future of their kin.
After much bloodshed Pentaaro's ship was defeated and he was presumably taken into custody to stand trial for his crimes against the Kentari people and its allies.