Monster Hunter Rise

The Mewocenaries are unlocked very early game as a means to send your buddies out to bring back some extra resources - including some items that can only be found through the Meowcenaries. These are found in the buddy plaza and can also be accessed from both your player house and the hub prep area. The NPC in the buddy plaza is a ninja-looking cat called Chief Kogarashi and can be found at the right-back side of the area.

Select an area, select some buddies, and send them off. They will be gone for five quests and the game will give you a notification on the side to inform you that they're done when you return from a quest.

The achievement is not as long as it sounds. As each expedition takes place over 5 quests, each mission they complete while deployed counts as a single quest towards the achievement. As such, you only need to dispatch the Mewocenaries 20 times before the achievement will pop.

If you add this to your rotation of things to do after quests you'll be done with this achievement long before you finish the game. As a comparison point, I unlocked this achievement shortly after unlocking high rank, having done all low rank quests prior.