Don't you think it strange that the First Ones are somehow more connected with the SL than with other realms, although they created all the Pantheons? We do not know anything about their connection with the Titans, although Blizzard once stated that the Titans also serve some purpose, like the Eternals Ones, but at the same time we see that the Eternal Ones really work, and the Titans do what they want (well, unless we assume that the FirstOnes put the desire to put everything in order in their heads). Eternals are a fixed number, Titans are scattered throughout the universe and it is not clear how many there are. Zeret Mortis itself forms kingdoms specifically for the SL, to get into it only the sigils of the Eternal Ones are needed (and not, for example, something from all the Pantheons). You can say that kzhada power has its own Zeret, but then why are there secrets in Zeret Mortis that can allow you to rewrite ALL reality, and not just SL. And in this Tomb we see the prototypes of only the Eternals, not all the Pantheons.
As if the Eternal Ones are the favorites of the First Ones.