It also occurs to me that the word "seraph" means an angel, so being sent by a higher power (possibly someone who's calling them to "return" to the world over and over and refusing to let them leave forever?) I think the drive to return, as in the intro log, is a driving feature of seraphs, who are the only ones who respawn in the same way every time they die and can only despawn (log off) by their own will, since the player character is the only non-mob life form. So maybe returning is a special feature of seraphs and the reason they are able to survive and create/fight in the ruined world? As opposed to the traders, who have to hide in their wagons, or the drifters, who can only wander and attack, or the creators of the ruins, who seem to be extinct as a society