There is only one mystery to be found in Eitri, named Remnants. You’ll find it in the southeastern part of Eitri, southwest of Jarn Herad, as shown in the screenshot below.
To begin the mystery, you’ll need to speak with a dwarf named Bolri, who roams around the area mentioned above. As you hear him speak, you’ll begin to realize that he isn’t exactly living in the same world as you. It seems he still thinks that Svartalfheim hasn’t been invaded, despite the fact that almost all the buildings around him are burnt and ruined. He’ll ask you to walk with him to his home, and as you walk he’ll begin to see that his house has been invaded. However, when he enters the house he’ll soon turn back to the delusion that his wife and son will be home any time soon.
Remnants Choices: What to Say to Bolri?
Once you’re in the house, you’ll need to pick up the toy Mjolnir, which you can find highlighted by using Odin’s Sight. At this point Bolri will respond, and he’ll ask you to stay, repeating the same words that he uttered when you first met him. At this point you’ll have to choose between two dialogue options:
Your wife and son are dead…
If you choose this dialogue option in response to Bolri he’ll become angry, stating that you’re either cruel or confused. He will ask you to leave his house and Havi will apologize, for what it’s worth.
Give my regards to your wife and son…
If you choose this option, Havi will tell Bolri that he has to leave to find his own son. He tells Bolri that he’s sorry, and that he hopes that Bolri finds what he needs.
Regardless of your choice between these two options, Bolri will go on living in his delusional state, but you will part on better terms if you choose the second option.