In the comics, her origin actually has her as the daughter of Loki, though not the version of Loki played by Tom Hiddleston in the MCU.
Odin gave Hela power over two key realms, though since Odin is actually Loki in the current MCU — long story — changes to Hela’s backstory seemed inevitable, and this appears to be one that Marvel Studios has made as we approach Thor: Ragnarok.
The comments underneath the video are, as you might imagine, a hot bed of angry folks who haven’t yet seen the movie and view this reveal as a pretty major twist.
There are some, however, who are attempting to come to this host’s aid (somewhat) by stating that if you are familiar with Norse mythology — or even the Thor comics — then you would know that Hela has a family connection to Thor Odinson.