(cmiiw) (spoilers) (pick a box tissues while ur at it)
if i rmb correctly this is the 3rd timeline(?) of them. the 1st timeline lilith died, enoch couldnt accepted it & sacrificed himself. in the 2nd timeline after lilth revived, the moment she knew enoch died for her, she used her premira to save him. basically its s self-sacrifice loop. oscar couldnt bear to see anymore so he sacrificed himself by using forbidden magic/curse(oscar my goat)
the side effect is he cant say anything abt it(he coughed blood in earlier chp) & hes destined to disappear and forgotten by others, like memory swipe(dont worry lili will save him later on)
novel spoilers, its not explicitly stated in current manhwa rn as it just revealed oscar is a regressor. i think in ch90 before the flashback started, at the sofa part, the words implying the self sacrifice moment(but it worded weirdly idk? its so flowery words maybe wait for the officials thats def ai translation)

In this chapter, in oscar’s Pov did he mean once the day he turned back times arrives, he will die??? Like if he turned back time on lilith’s 18th birthday, then when it’s lilith’s 18th birthday in this timeline, he would die?? Someone spoil meeeee