Trivia: "Blood Wars" has been confirmed to be the final "Underworld" to star Kate Beckinsale, and possibly the final film in the series. It was originally intended for there to be one final entry in the series featuring Beckinsale's trademark character Selene to finish off her storyline, but Beckinsale stated in late 2018 that she felt she had done "enough" films in the series and wasn't interested in reprising her role for a sixth film. After the film under-performed at the box office, there has also been no news on any future films, with series co-creator Len Wiseman instead expressing interest in rebooting the franchise as a television series.
Trivia: The only entry in the series to not by co-written by either of the series co-creators Len Wiseman or Danny McBride. McBride (not to be confused with the actor of the same name) co-wrote the first three films, while Wiseman co-wrote the first four films.
Trivia: Marked the first time an "Underworld" and "Resident Evil" film were released in the same month, when it was released only weeks apart from "Resident Evil: The Final Chapter." Both franchises are produced by Sony, and share many odd coincidental thematic connections. (Including a super-powered female protagonist, a tragic romance, supernatural elements involving the undead, etc).
Answer: Amelia was a Vampire Elder. She had responsibilities to the coven, to be gone for days or weeks would be normal, but months. Viktor had a suspicious nature. After discovering his daughter's affair with Lucian and the rebellion of the Lycans, he probably feared another betrayal.