Read

Speculation is required as part of the answer to this question, since the narrative of Jupiter Ascending (2015) doesn’t implicitly say one way or another. But there are context clues that offer a likely scenario.

Balem (Eddie Redmayne) never directly admits to being the one who murdered Seraphi, but the film does heavily make that implication. All of the Abrasax children tell different colored stories about what happened with their mother, and it’s likely they’re all unreliable and lying to some degree. After all, each sibling has something they’re trying to gain over one another, and Jupiter (Mila Kunis) is integral to each.

It is implied that Balem murdered their mother due to the reasons that Titus (Douglas Booth) originally gives Jupiter - that Seraphi started having second thoughts about the family enterprise of harvesting humans to produce RegeneX. Balem says his mother was fighting with him and demanded that he kill her, saying she hated her life. It seems unlikely that would be true given that Seraphi wrote Jupiter into her will, as if she knew the inheritance shouldn’t fall in her children’s hands. It seems likely given Balem’s violent tendencies, mental instability, and peaks of rage that he murdered her out of anger because she was threatening the future of RegeneX. Perhaps he was unable to cope with what he did, so he invented the story about her asking for death to justify the murder.