There are multiple reasons why American actress Elizabeth Röhm left the hit show Angel in season 2. The series - which aired for five seasons from 1999-2004 - is a spin-off from Buffy the Vampire Slayer and, like Buffy, was created by Joss Whedon. The show centers on the ongoing trials of Angel (David Boreanaz), a vampire whose human soul was restored to him by a curse as a punishment for murdering one of his own. Angel is a character first seen in the series premiere of Buffy, titled "Welcome to the Hellmouth." In the spinoff show—which has many crossovers with Buffy—Angel's soul torments him with guilt, remorse, and anguish. Angel works as a private detective in L.A. as an attempt to help people and save their souls. In the meantime, of course, he fights demons.
Röhm played Kate Lockley on the show. Kate is an LAPD detective who first appears in season 1, episode 2, "Lonely Hearts." Until she meets Angel, she's unaware of the supernatural activity present in the world. She helps Angel bring down a killer early on, and after that, he helps her whenever she needs it. The two characters assist each other with their respective cases, though their relationship with one another is often strained.
Röhm appeared as Kate in 15 episodes of Angel, spread across seasons 1 and 2. During Angel season 2, though, she left the series due to conflicts as well as other plans. Her sudden departure from the TV show let many viewers down, as her character's arc was incomplete. At the end of her time on the show, Kate becomes completely obsessed with supernatural cases, is fired from the LAPD, and attempts suicide. Angel saves her and they have a deep conversation. After that, she never appeared on the show again, though she is briefly mentioned in season 2, episode 18, "Dead End", with Angel explaining he no longer has a LAPD connection.
The main reason Röhm left the show in the middle of Angel season 2 is because she joined the cast of Law & Order. She appeared in more than 80 episodes during her four years on the show, playing the regular character Serena Southerlyn, an assistant district attorney who first appears in the 2001 episode "Who Let The Dogs Out?" Serena became a fan-favorite character in her years on the hit crime drama series. The role lasted through the fifteenth season of the show. But Law & Order wasn't the only reason Röhm left Angel. By the second season of Angel, Röhm also had her own show on TNT called Bull, an American drama series that ended up being canceled after only 12 of 20 planned episodes were aired.
In 2015, Röhm discussed her leaving Angel during an "Ask Me Anything" session on Reddit, explaining that in the first season of the show, she was a part of the original cast and it was an exciting time. Once she had other shows she was a part of, though, it became difficult for her to juggle the multiple commitments and roles. "It would be impossible for me to go from New York [for Law & Order] to Los Angeles for Angel and we had a great opportunity for it to end dramatically," she said. Röhm has stated that Kate Lockley's ending on Angel was "very satisfying," but many fans of the series certainly felt the opposite way, and were disappointed with Kate's final episode. Kate had been an extremely interesting character who was slowly becoming darker and more complex; her story ended too abruptly and felt unfinished.