Its known that nemesis bosses disappear after a certain time, a lot of bosses like zarabustor, foremen kneebiter, big boss troliver, big bad wolf, etc... disappear after about an hour +-
But some nemesis bosses, that is a bag bosses, like tyrn, shlorg, the welter, stay for more time than de other bosses.
The question is: how long do this bag bosses disappear?