Lagertha's death in "Vikings" Season 5 is imminent following the death of Aslaug in Season 4 episode 14. Speculations are rife that Ivar will avenge his mother's death, but he does not carry out the killing himself. Instead, he asks his brother Sigurd to kill Lagertha.
Lagertha is aware that her death comes at the hands of one of Aslaug's four sons, as what the Seer told her. However the question remains, who among the former Queen of Kattegat's sons will kill her?
Screener TV analyzed the extent of each son's drive to avenge his mother's death. Among Aslaug's children Ubbe, Sigurd, Hvitserk and Ivar, the latter is the most likely to want to see Lagertha dead. According to the site, Aslaug's death greatly affects Ivar more than his brothers.
Ivar the Boneless is the closest to Aslaug, since he grew up surrounded by her love and care. She also taught him how to survive. Not to mention, Ivar is the bloodthirsty and vengeful one among his siblings. It would be easy to assume that he wants to see Lagertha dead, or worse, kill her himself in "Vikings" Season 5.
However, Ivar also does not want to disappoint his father Ragnar Lothbrok, now that the latter has placed so much trust in him. Killing Lothbrok's first love would only take that trust away and anger his father. Instead, it is likely that Ivar lets Sigurd do the job. After all, Sigurd initially wanted to kill Lagertha early in "Vikings" Season 4.
Regardless, according to Movie Pilot it is still likely that Ivar the Boneless himself kills Lagertha in "Vikings" Season 5. The site referred to a scene in Season 4 episode 16, when he threatened to kill Lagertha after Aslaug's death. Ivar had said, "One day I will kill you Lagertha." Perhaps, his taunt was already a hint to Lagertha's death under Ivar's hand (see video below).
