"Turns out Cortana's big dramatic death scene in the last game wasn't for realisies, but one could kinda predict that from the mere fact that there is a Halo 5 at all. It doesn't take a giant space-protractor to calculate that Master Chief and Cortana are the only marketable faces of the franchise; which is not even because they're good or interesting characters. It's only because Mr. Chuffy is the protagonist and Cortana flaps her big blue knockers about like a gelatin dessert on a merry-go-round. The funny thing is, even in-universe, everyone seems to realize that Mr. Chuffy and his little blue titty-monster are the only characters of any importance. So when Mr. Chuffy reports having a weird dream about Cortana being alive and calling him to distant planet, not a single person so much as hazards the possibility that it was just a dream and maybe he'll forget all about if they buy him a new wank-doll for Christmas. No, they're all like, "Ooh, this is serious! We better go to that planet, then!""