"Once Upon a Time in Mondstadt" is a special food item that the player has a chance to obtain by cooking "Pile 'Em Up" with Diluc. The recipe for "Pile 'Em Up" is obtainable from Good Hunter for 5,000 Mora after reaching Adventure Rank 40.
"Once Upon a Time in Mondstadt" increases the party's critical rate by 20% and critical damage by 20% for 300 seconds. Like most foods, this has no effect for other players in Co-Op Mode.
- To celebrate Diluc's birthday, the Teyvat Food Notes published a real-life recipe for "Once Upon a Time in Mondstadt." In it, Diluc tells the Traveler that he chose the name for this dish on a whim, though it is apparent that he is simply hiding his real reason.
- The following birthday mails included "Once Upon a Time in Mondstadt":
- Diluc's 2021 Birthday Mail (1 "Once Upon a Time in Mondstadt")