Alexander Selwyn was an employee of the Canaan Corporation.
After Selwyn's wife Isobel Selwyn died of cancer in 2018, his friend, Eldon Tyrell had a replicant created to be identical to her. As payment, the two arranged to give the Tyrell Corporation full custody of his daughter Cleo, who possessed a rare genetic mutation which was linked to longer life expectancy.
Blade Runner Aahna "Ash" Ashina was given the assignment and met with Selwyn at his Santa Barbara home. He informed her that his wife, daughter, his chauffer Arkady, and his wife's spinner had last been seen at Lydia Tyrell's birthday party. He denied any significant problems in his and his wife's relationship and declines to bring public attention to the disappearance, fearing it would attract enemies.
He soon became dissatisfied with Ash's progress, leading to her removal from the case.
Selwyn and a bodyguard later interrogated the Skin and learned of El Santuario, where Isobel and Cleo sought refuge. Accompanied by armed Tyrell personnel, Selwyn went to El Santuario, but was unable to retrieve Cleo, who escaped with Ash.
By 2026, Selwyn had gone off the grid and was producing bootleg Nexus-8 replicants under the Canaan Corporation. He assigned London-based Blade Runner Hythe to track down Ash and Cleo in the Off-world colonies and another Isobel to assist in this plan. After Hythe's failure, Selwyn assigned another Hythe to finish the first's job, as Ash had returned to Earth and was on his trail. He and four Hythes – along with Cleo's fully-grown artificial lion – awaited Ash at Selwyn's former Santa Barbara home.
After explaining his ideas to replicants to be "a better us" to Ash, a fight ensued, with the ex-Blade Runner managing to kill two Hythes and the lion before slipping out of the mansion. Selwyn and the remaining Hythes quickly followed and used a remote to shut down Ash's spine brace. Just then, a spinner arrived, containing Cleo and Isobel. Cleo confronted her father, demanding him to confirm that his initial reason to find her was so that she could be given to Tyrell to be experimented on. Selwyn confessed to this, but plead that they now could become a family. Cleo hugged him before going to the injured Ash. Isobel then went over to him and killed him by breaking his neck.