MONSTER HUNTER: WORLD

This achievement requires you to have access to which is a new area of the world which you will unlock after defeating the final boss of the Iceborne story mode.

This new area contains multiple regions which resemble the five regions in the base game; however, these regions are all packed tightly together in a single zone. Initially, you will only have access to regions corresponding to Ancient Forest, Wildspire Waste, Coral Highlands, and Rotten Vale.

Each of these regions has a level associated with it. Upon first reaching the new area, all of the regions are at Level 1. Monsters corresponding to the level of the particular region they are native to will appear and disappear over time. As you level the regions up, more difficult monsters will begin to appear.

Performing various activities in these zones will increase the level of the zone the monster is associated with. Activities that raise region levels include hunting monsters, picking up monster tracks and trapping monsters (even without successfully hunting them). However, raising the level of one region may actually decrease the level of one or more other regions. This means it's easiest to concentrate on one region to level up. You can find a guide explaining in more detail how this level increase/decrease system works here: https://imgur.com/a/r8KwpxJ.

Full progress toward this achievement is locked behind your Master Rank. Prior to MR 49, any one region many only be raised to Level 4.

At MR 49, your MR rank will be locked. You will receive a new quest from the Field Team Leader: Completing this quest will unlock your MR rank, allowing you to progress past MR 49, while also allowing you to level individual regions to Level 5. Any progress you gain while your rank is locked will be retained and granted to you.

At MR 69, your MR rank will be locked once again. You will receive a new quest from the Field Team Leader: Completing this quest will unlock your MR rank, allowing you to progress past MR 69, while also allowing you to level individual regions to Level 6. Any progress you gain while your rank is locked will again be retained and granted to you.

At MR 99, your MR rank will be locked one last time. You will receive a new quest from the Field Team Leader: Completing this quest will unlock your MR rank for the final time, allowing you to progress past MR 99, while also allowing you to level individual regions to Level 7. Any progress you gain while your rank is locked will again be retained and granted to you.

Once having done all of the above, simply continue performing various activities as needed to level one region to 7.

Side note: there is one other region in the new area which is hidden from you at first, the region corresponding to Elder's Recess. Accessing this region requires you to complete the quest However, you can obtain the achievement without even doing this if you so desire.