Important information.
Down below I’ll explain what to do to get an additional immortalite stone while following a little side story.
Completing the starting part of the side story before killing the Bulwark is not necessary, you can just complete everything after you’ve killed him.
1.The Cave
Just before the Bulwark, there’s a staircase where you’ll see an entrance to a cave.
If you have already killed the Bulwark, read this section but don’t do anything yet go read the second one too.
From here on I would recommend talking to every little creature that has the dialogue option if you want to follow the side story of course.
Enter the cave and don’t forget to go to the left there’s a tome.
After that, you’d want to re-enter the cave until it stops changing the environment.
2.Returning again
Now you can only continue if you’ve defeated the Bulwark.
Make sure you have 10 spare minutes before doing this part because once you get the final dialogue, you will have to stay in the cave, otherwise you’ll lose out on the immortalite.
Re-enter the cave until the dialogue asking you to wait 10 minutes appears, now wait 10 minutes and do not leave the cave.
Enjoy your immortalite.
3.Post scriptum
I hope that helped you.