One very low key but crucial (long term) element of the newly released monster-catcher is Pokemon Legends: Arceus satchels. Satchels are a Dark Souls-like asymmetric multiplayer element, where items can be left behind by players online if they faint (are attacked/die from a monster in the field). Make sure you’re always aware of them!
Check them out on the map
So here’s the easiest way to locate these tiny little boxes, which can be hard to spot randomly. Load up the main map, the same one you use to fast travel with (with the “-” button).
Then look for the little white treasure chest icons: those are all Pokemon Legends satchels left by players.
To find them more easily, you can put an objective flag marker down, which is highlighted in a very obvious way while you’re out in the overworld. You can only put one flag marker down at at time, so just repeat the process, going back to the menu, to place the flag, then head from box to box.
All you need to do to collect it is press the A button while next to it: that’s it!
Turn them in for rewards:
So what do you actually get out of these satchels? Well, merit points and bonus items. You’ll get a quick item bonus when turning them in at the lost and found (or through the network tab on the satchel [up direction pad] menu, which you can do in the field), as well as merit points.
Wait lost and found? Yep, that’s located right here on the map in the main hub (Jubilife Village), marked in the red circle, in Pokemon Legends.
Head there, talk to Simona the NPC, and you’ll be able to initiate trades (locally or online) as well as exchange merit points, or MP, for items (“I want to get items”). These are typically long game evolution items (and pricey ones at that, with 1000 merit points as a baseline), but it helps to start building a steady base of MP early!