There's an alley surrounded by buildings of stone, metal, and wood. The pavement is stone and very uneven. The air smells of foul things that aren't just garbage or sewage. The alley connects two larger streets where pointy-eared humanoids with brightly colored hair walk or ride flying constructs. There's a sign with a picture of a person in red armor and a caption in an unfamiliar alphabet.
Eventually some of them have made it up to the tops of the cliffs nearby and can look down on him with their gleaming yellow eyes. None of them look like the creature from the picture he was shown, but they vary a lot and they all have the same kind of gem and very similar metal armor over their heads.
"You're just a human with funny ears," says one of the ones looking down on him literally as well as metaphorically. "Are you willing to offer anything for peace or just beg us not to destroy an untrustworthy civilization of people who worship our worst enemies?"
He is silent for a couple seconds while he works out what he will do if they decide to jump on him from up there, but then he composes an answer. "I don't know what you want. I can do magic. I can talk to the people in the city, if there's anything you'd like to say to them. I could try to convert them to my religion instead but I did consider it and don't think I'd be very good at it."
"...not directly but my goddess was once mortal and her god at that time did do some interplanetary adventuring the details of which were not recorded, and he was Neutral rather than Good which can cover a multitude of errors. To be clear I don't think it was necessarily him, I just can't rule him out. It definitely wasn't Her."
"The only things I know about the stone were in the book I read. It said they need it to keep the machines in their city working. Do you know if that's true or not?"
"The book could be mistaken. I don't know who to talk to who would know differently, but I can try, if it might help."
"If I were doing this recreationally then that might matter. I have seen big and toothy creatures before."
"There is only one of me. If I am killed taking unnecessary risks there is not going to be another. Talking to your leader strikes me as a necessary risk and venturing into your retreat when I can speak to you from here does not."
"...that does sound like it would be very hard to come to any kind of agreement on."
"Hello. I'm Select Blai Artigas and I am from another planet and here by accident."
"Welcome, Select Blai Artigas. We are likewise from another planet and here by accident. How may we help you?"