Under a Dark Sun cast and character guide: Who plays whom in Netflix's latest thriller show?

Under a Dark Sun (Qui Sème le Vent) is indeed less a traditional whodunit and more a multi-generational tragedy, where family trauma is passed down from one generation to the next, mutating victims into perpetrators while love is scarred by betrayals. The major twist comes when Arnaud is killed, and Alba finds that he is inheriting his estate in equal parts with their children.

She gets to know about her origin, which invites more struggle for her. She is framed for Arnaud's murder, while Manon being the real killer, becomes her lawyer to divert the case. Eventually, Alba and Manon agree on a way to close the case and come out of it, without justice but with freedom. Under a Dark Sun portrays a generation of a family and involves a brilliant ensemble cast. Read on to know a clear Lasserre family tree and character breakdown.

Who plays who in Under a Dark Sun, Netflix mini TV series

Under a Dark Sun cast and character guide (Image Via Netflix)

Thibault de Montalembert as Arnaud Lasserre

In Under a Dark Sun, Arnaud is the patriarch, a seed from which the rot began within the family. He owns the family business and is eventually killed by his granddaughter, Manon, out of vengeance for abusing her mother, Josephine. Unlike typical absentee patriarchs, Arnaud stays hands-on, even overseeing seasonal workers and flower picking. This closeness to labour, however, hints at deeper exploitation — not just managerial control, but grooming and abuse under the guise of authority.

Arnaud’s relationship with Beatrice is deeply dented as he was emotionally cold, unfaithful, and sometimes violent. But Arnaud pays off her gambling debts not out of love but out of a guilty recognition of what she has endured.

Isabelle Adjani as Béatrice Lasserre

Beatrice is a complicit survivor and the wife of Arnaud. She becomes addicted to gambling and marries Jaques, a family enemy, to protect her control over the estates. Her children trap her in a psychiatric facility after Arnaud's death, echoing what happened to Josephine. This later came as a calculative motive and was not just a convenience, as they wanted her out of the estate affairs.

Her “materialism” is actually a desperate attempt to regain power in a world where emotional needs were never met, and money is the only shield she has left.

Guillaume Gouix as Mathieu Lasserre

Mathieu is the son of Arnaud and Beatrice. In Under a Dark Sun, he is shown as controlling and emotionally cold; he wants to sell the estate just like the other family members. He is married to Josephine and is the father of Manon. He abandons Josephine emotionally and is complicit in institutionalizing her. He is not fully like Arnaud, but his dark shadow.

Mathieu doesn’t just mirror Arnaud’s behaviour; he repeats it, unconsciously and pathetically. He wonders why Josaphine left him, but never gets to know that his own father orchestrated the same. His portrayal suggests how he has ingrained some dysfunctional behaviours of his father.

Louise Coldefy as Manon Lasserre

Daughter of Josephine and Mathieu, is portrayed as a lawyer who then comes forward to defend Alba. Manon kills her grandfather, Arnaud, after knowing the abuse happened with her mother, Josephine. When Manon makes her way to the psychiatric clinic, she decides to take revenge by killing Arnaud and then hampering Alba's case by being her lawyer.

Manon's motive behind framing Alba is that her son, Leo, had killed Hadrien, her brother, thinking he was the one who kidnapped him, but it was actually Manon who also has the same tattoo as her brother.

Ava Baya as Alba Mazier

Alba finds her name in Arnaud's will and later gets to know that she is Mathieu's daughter, raised away from the estate. Mathieu had an affair with Nadia once a flower picker from the farm, and he got her pregnant with Alba. Alba's mother was then forced to leave the estate and raise her alone.

Some time later, Nadia writes a letter to Arnaud telling her to make Alba his heir to secure a good future for her daughter. Arnaud then added her name there without telling her anything. She is framed by the family for Arnaud's murder as she is the one found near the body. She navigates shock, betrayal, and trauma to eventually reclaim her identity, coming to an agreement with Manon, which saves both of them.