Enkanomiya is shrouded in mysteries, including the existence of afterimages during Evernight. Kabayama is an interesting character who you can meet by chance in the most discreet way possible. Before starting this Hidden Exploration Objective, switch your daylight settings to Evernight.
Head to the area circled in the image below. It's a bit hard to find in the dark, so keep your eyes peeled.
You'll find a gap in the wall at the side of the Dainichi Mikoshi. Enter the secret room, and you'll find nothing—except for a suspicious-looking stone. Interact with the oddly-colored stone to sit on it and prompt the afterimage of Kabayama to appear.
Even in the ancient world of Enkanomiya, saving seats is a thing. And you've just sat on Kabayama's favorite seat. But he's alright with it—in fact, he's enthralled by your traveling experience and wants you to visit his favorite spots in the region.
Kabayama's three favorite places are circled in the images above, and they can be visited in any order. Upon reaching each location, you'll find a stone on the ground and a lantern hanging from a tree or structure.
Sit on the stone to prompt a dialogue from Paimon. Then climb the tree or structure to reach the lamp, which you can interact with to find out snippets of Kabayama's past. The same formula applies to all three special spots.
After completing all three, head back to Kabayama in the discreet room to tell him about your adventure to complete this Hidden Exploration Objective. Kabayama tells you he doesn't have much to give but leaves you a Precious Chest anyway. You'll also unlock the Wonders of the World Achievement called "What Difference Does This Make?"
Check out our guide on How to complete the Collection of Dragons and Snakes World Quest in Enkanomiya in Genshin Impact to unlock even more secrets hidden beneath the last day of Byakuyakoku.