Kim Bodnia as Konstantin Vasiliev, Villanelle's handler. Owen McDonnell as Niko Polastri, Eve's English-Polish husband, a teacher. (series 1–3) Sean Delaney as Kenneth "Kenny" Stowton, Carolyn's son, an ex-hacker who has been recruited by MI6. He later becomes a journalist for Bitter Pill. (series 1–3) Darren Boyd as Frank Haleton, Eve's supervisor at MI5. (series 1) David Haig as Bill Pargrave, Eve's MI5 associate who comes with her to MI6. (series 1) Kirby Howell-Baptiste as Elena Felton, Eve's assistant. (series 1) Nina Sosanya as Jess, an experienced MI6 agent now working as a part of Eve's team. (series 2) Edward Bluemel as Hugo Tiller, a wealthy Oxford graduate, who is working as a part of Eve's team at MI6. (series 2) Henry Lloyd-Hughes as Aaron Peel, the heir to a tech company following the assassination of his father, mogul Alistair Peel. (series 2) Adrian Scarborough as Raymond, a member of the Twelve and one of Villanelle's former handlers. (series 2) Raj Bajaj as Mo Jafari, a new MI6 agent working for Carolyn. (series 3) Turlough Convery as Bear, Kenny's co-worker at Bitter Pill. (series 3) Steve Pemberton as Paul, an MI6 supervisor. (series 3) Danny Sapani as Jamie, Kenny's boss at Bitter Pill. (series 3) Harriet Walter as Dasha Duzran, a hard-bitten one-time Olympic gymnast turned spy, Villanelle's former trainer and mentor. (series 3) Gemma Whelan as Geraldine, Carolyn's daughter and Kenny's older sister. (series 3) Camille Cottin as Hélène, a member of the Twelve. (series 3)