To successfully unlock the upgrade path and access the DLC monster Deviljho in Monster Hunter: World, as well as similar DLC monsters, players must follow a structured progression as outlined below:

Step-by-Step Guide to Unlock Deviljho

1. Achieve Hunter Rank 13 (HR 13):
– Before you can access Deviljho, you need to reach a minimum Hunter Rank of 13. This level is required to initiate the special assignment associated with Deviljho.

2. Progress Through the Main Story:
– Continue progressing through the main story and complete the quest titled “??? Rathian.” This quest serves as a pivotal point in unlocking Deviljho’s appearance in the game.

3. Encountering Deviljho:
– After completing the aforementioned quest, Deviljho will start to appear as an invading monster in 6★ and 7★ quests and in high-rank expeditions. You will receive a prompt when Deviljho enters your world.

4. Locating Deviljho:
– To find Deviljho easily, use your world map. Look for a “???” monster icon that indicates its location. If you don’t see this icon, travel to various areas and check the map again until its location appears.

5. Gathering Evidence:
– Instead of directly hunting Deviljho, you can gather evidence by collecting its tracks or capturing it during expeditions. While you can also kill Deviljho, tracking or capturing it is recommended as it aligns more closely with the evidence-gathering process.

6. Return to Astera:
– Once you have collected sufficient evidence of Deviljho, head back to Astera. There, locate the Wyvernian Scholars, indicated by a blue exclamation point on the map.

7. Triggering the Special Assignment:
– Interact with the Wyvernian Scholars to trigger a cutscene that will unlock the special assignment titled “The Food Chain Dominator.”

8. Completing the Special Assignment:
– Complete the special assignment hunt against Deviljho. Once you finish this quest, Deviljho will be fully unlocked, and you will gain access to upgrade paths and unique rewards, such as the Dragonproof Mantle, which enhances your resistance to dragon damage.

General Notes on Other DLC Monsters
The steps outlined above can be applied to other Capcom post-launch DLC monsters. The general workflow involves:
– Reaching the required Hunter Rank.
– Encountering the monster through invasions or targeted investigations.
– Gathering evidence and completing specific special assignments by interacting with NPC researchers in Astera.

By following this systematic approach, you will be well-equipped to unlock and hunt Deviljho, along with accessing the associated upgrade materials and gear needed to enhance your hunting experience in Monster Hunter: World.