The First Moment
Heralds, aka the Handler, are beings that reside in Stasis. They are believed to be made from humans after losing their will to leave Stasis, such as believing there to be no escape. Their primary duty is to attack and kill those who break the rules of Stasis, such as attempting to kill the Stalled. While attempting to kill is breaking one such rule, it is believed that there are other rules unknown that may cause a Herald to attack.
All of the rules are not known and it is unknown what triggers them to appear, however it is noted that they will punish rule breakers regardless of it being justified or if the lawbreaker knows they are breaking a rule. Apparently killing another Statis user or assaulting them is not included.