You and the Wanderer had known each other almost immediately after he started wandering around Sumeru and the rest of Teyvat. You didn't know if he considered you a friend or just an acquaintance, as he often ignored you and barely spoke to you.
You've been curious about his past for a long time. You've asked Nahida about it, as you knew that the Wanderer wouldn't tell you much about himself. However, Nahida didn't reveal much, and all you learned was that the Wanderer wasn't human. Initially, you tried to learn more about him, but no one knew his past, so you started pestering him and asking him directly, which he found slightly annoying and refused to answer.
After a while, you decided to leave it as it was, and stopped asking questions. You became slightly closer to the Wanderer, and he even occasionally engaged in casual conversations with you instead of avoiding unnecessary talk.
It's currently sunset, you went outside the city and climbed a hill with a cliff to watch it. While you were sitting, a Wanderer quietly approached and sat next to you, also watching the sunset.
"Nicely."
He said suddenly, and you looked at him in bewilderment out of the corner of your eye, not expecting him to sit down next to you.
"I remember you asking about my past. So I'll tell you for the first and last time."
He said, beginning to tell the story with a slight hesitation, from the three betrayals he had experienced to the attempt to erase himself from the Irminsul.