Ben Kendrick was a Incubus, turned by Lillith with the sole purpose of retrieving fellow Succubus Erica Reyes so she could turn Erica into a stronger type of Succubus known as a Malach.
He was turned into a Incubus by Lillith, a centuries-old Demon who needed a partner with "eyes and ears" around the town to help her with her agenda, which was to take Erica Reyes and turn her into a Malach. She felt sympathy for Ben's hopelessness regarding where he was going in life.
Pretending still to be human, he continued working as a bartender at the Grill and was chivalrous enough to come to Elena's aid when she was being hostile toward Seth, though this later turned out to be revealed as part of his and Lillith's plan.
Lillith and Ben had a somewhat romantic relationship, although she basically used Ben as a tool in her plot. Ben's task to aid Lillith in opening the tomb was to seduce and kidnap Emery Whitehill with the intention to use her to lift her ancestor Emily's spell that kept the tomb sealed. They kidnapped Emery to use as leverage to motivate Elena to perform the spell. Both were later rescued by Seth, who burst into the hotel room where Lillith and Ben were staying and burnt Ben with sunlight reflected from an iron mirror. As Ben cowered behind a bed, Seth warned Ben to leave town, though he chose to ignore the threat.
Being a newly turned Incubus, Ben was boastful and arrogant, reveling in his immortality and newfound strength and seductive appearance. It is likely that he was not changed against his will, as when Seth told him that all Lillith cared about was gaining power, Ben replied that it didn't matter because she had already given him what he wanted. He told Seth he wasn't strong enough to beat him because of his refusal to consume human hearts, which gave him more diminished abilities than Ben, but since he was much older in addition to being a werewolf-incubus hybrid, Seth easily subdued him and used a flamethrower to set him ablaze. Ben managed to extinguish the flames, but was weakened by the pain, allowing Seth to transform and slash him apart with his claws, killing him.
After killing Ben, Seth burned Ben's body to prevent him from regenerating (though it's later revealed that Incubi cannot regenerate after death).