SureAI

for anyone with the same question, that was answered in the Steam Forums. the description will be changed.

When I went through the quest <<Hope for the end of the world>>, I did not put on a deep-sea helmet and died, and the last save was at the time of my death. The nearest save on the <<Sins of Our Fathers>> quest. I don't want to go through all over again.

Do you not have at least multiple Autosaves and one Quicksave nearby?
(many fixed and different savegames are very important)
Have you installed any mods that might cause an error?

No, there is only auto save at the time of my death, there are no quick saves either. There is only save before the battle with the Lightborn. I don't have any mods.

The current Nehrim automatically creates 4x normal autosaves.ess and 3x autosavelong.ess. That is at least 7x game saves.
In addition there are Quicksave (by default Quicksave is F5 and Quickload F9) and the manual save points,
which you should not only play technically, but mainly because of the engine.
Without a current saved game (before this problem) we can't help of course, because we would have the same problem.

But if you should play the old Nehrim version (non steam) and without OBSE, you have a very small chance by renaming your autosave.bak
to Autosave0.ess in your game folder.

PS: in Bethesda games, as well as in games from SureAI (same engine), it is often needed to save more than one savegame.