Cain

Initially, Caine (played by Marcus Pierce) appears calculating, reserved, and respectable. Like Lucifer, he is charming, charismatic, and handsome. He seems to despise police officers who have a history of committing crimes, and immediately dislikes Dan for helping Malcolm Graham. He also seems to dislike Lucifer, considering him reckless, and later calls him an idiot for taking on "The Sinner."

He also proved to be a compassionate man: he told Lucifer not to involve Chloe Decker in the search for "The Sinner" so as not to endanger the life of her daughter, Trixie. Pierce claimed to admire Chloe as a detective and said he came to Los Angeles solely to finally see her in action.

However, it was revealed that much of Kaine's personality as Pierce was a pretense, as he wanted Chloe Decker and Lucifer Morningstar to stay away from the Sinnerman decoy, fearing it might lead to him. Pierce admitted to Lucifer that the decoy belonged to his friend and right-hand man, but he killed him because he had gotten out of control and needed to be "taken out."

His apparent admiration for Chloe was also proven to be nothing more than a lie. He did indeed come after Chloe, not because of her detective skills, but because he knew her presence made Lucifer vulnerable, and he wanted to see if it would work on him too.

A notable trait of Cain was that he deeply despised his brother Abel, whom he considered an "assat," and felt no remorse for killing him. However, after Abel was temporarily resurrected, Cain was able to fully reconcile with him after all those years of hatred.

Pierce's greatest wish was to finally die, to be freed from the curse of immortality. He was tired of being alive. In his words, "I've walked this earth for thousands of years. I've seen it all, I've done it all. I've seen everything I've ever known turn to ashes again and again." Pierce agreed with Lucifer, who compared it to hell.

The body of chemistry teacher Jun Lee (real name Sandra Jung) is found in a Los Angeles suburb. She was a former chemist for the Korean Power gang and a producer of ecstasy (aka K-Pop). However, Sandra faked her death, stole money from her employers, and started a new life in the suburbs.
Lucifer and Lieutenant Marcus Pierce (aka Cain) are forced to go undercover, posing as a married couple (aliases Mark and Luke) to track down a killer. Their task is to infiltrate the victim's circle and find clues.