The reason why the early remote exploration mode of underground castle often faces death is that the capacity of the backpack is too small, so players can't deal with the unknown dark test reasonably. Here's how to expand the backpack in the underground castle.
1. Click the page of the underground castle to enter the production options, and in the options, you can choose some leather as raw materials for expansion. It is also feasible for players to obtain raw materials of leather through expeditions or directly purchase from stores. In short, it is relatively simple to complete the first expansion, and the first expansion can make backpacks The capacity reaches 20
2. The second expansion still needs leather as raw material, but the number of raw materials has increased. The method of obtaining it can still be obtained through purchase or fighting. It is suggested that players should purchase it through stores. After upgrading to leather package, the capacity can reach 30
3. For the third time, players don't need to use leather, but can't choose. The method of obtaining is the same as the previous two times. After upgrading to jute bag, the capacity will be upgraded to 40
4. The fourth, fifth and Sixth Expansion still needs cloth, but the consumption of cloth is the most in the whole process. Therefore, after upgrading to wool bag, the capacity also reaches 70
5. In the seventh upgrade, we need to use iron as raw material. After upgrading to iron box, the capacity reached 80.
The above is about how to expand the backpack in the underground castle. Although there will be an eighth expansion in the future, there is no ability to collect steel materials so far, so the upgrade has not been successful so far.