I just learned about Rost's backstory and would love a game/movie about it.
I completely missed it on both previous playthroughs because it's very easy to do so, it's a dialogue option with Teersa after exiting All Mother Mountain, it's a classic revenge story, Rost was happily living in a village that used to exist in the Sacred Land with his mate and daughter, then 12 outsiders broke into the Sacred Land and took the village hostage while looking for something in Devil's Thirst, they killed almost everyone in the village, in his immense grief, Rost chose to become a Death-Seeker, one who spiritually dies in the ritual and leaves the Sacred Land seeking death, and he does so, traveling throughout the world and even going to places we have yet to see in the franchise, killing each outsider one by one, but not before being gravely wounded and barely making it to the border of the Sacred Land as he wished to die as close as possible to it but knew not to cross the border willingly but a Brave woman who lost her mate and two sons to the outsiders broke taboo and pulled him across the border and brought him to the Matriarchs, they nursed him back to health and instead of sending him back out of the Sacred Land they made him an outcast and told him never to tell anyone of this exception, I'm a sucker for this type of story and just really want to see it given more attention.