Lenik
Lenik of Vulcan is a 131-year-old Vulcan and an extremist member of the Reya-Laialara. The commander of a Cardassian Vasad class Frigate, the Miran's Tifar, that has been re-purposed for pirating and navigating through the Shoals, he's made a name for himself for his brutal tactics, uncompromising devotion to a fundamentalist version of the Reya-Laialara's ideals, and his ability to thus far elude authorities. Lenik is suspected of having committed several murders simply for the emotional experience.
History
Lenik was a priest on Vulcan up until the early 2350s, and showed no signs of radicalization or emotion. What happened during this time period is unclear. However, when Lenik re-emerged outside of Federation space twenty years later, he was a very different man. Shunning Vulcan philosophy in exchange for emotions running rampant, he didn't take long to take to apparent piracy.
Criminal Acts
Lenik is suspected of having committed several murders between the early 2350s and 2390s, though his involvement was never decisively proven - the evidence was circumstantial at best. His modus operandi has varied and evolved over time, and seems to involve making his victim suffer as long as possible before finally extinguishing their life.
Lenik has committed numerous acts of piracy. Some brutal, others almost gentle. Survivors have reported a range of behaviors anywhere between psychotic and violent, and gentlemanly or serene, like what most would expect from a Vulcan.
Most recently, Lenik led a biological weapons attack that was largely foiled by the crew of the USS Montreal. With his vessel severely damaged, his last known course was toward Karakka. When intercepted, he'd set it on a collision course with the colony. With the Montreal herself damaged and with no other recourse, Commander Mei'konda evacuated the Montreal, set her self destruct, and destroyed both vessels to prevent damage to the colony.