> For the complete documentation index, see [llms.txt](https://castleoverlord.gitbook.io/whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://castleoverlord.gitbook.io/whitepaper/getting-stronger/resources.md). # Resources Players can get stronger by earning resources through battles and spending these resources to upgrade units. There are six types of resources in Castle Overlord, which consist of 1 currency and 5 materials. Every resource type is a cryptocurrency token, and all resource earning/spending activities are treated as on-chain transactions. 1. Currency: Gold 2. Material: Red Gem 3. Material: Black Gem 4. Material: Yellow Gem 5. Material: Green Gem 6. Material: Blue Gem Both gold and materials can be acquired by playing PvE or PvP battles. In PvE battles, the amount and type of resources awarded are predetermined according to the selected stage. However, in PvP battles, these resources will be determined by how many towers/castles the player succeeded to destroy. Different types of towers/castles will yield a different amount and type of resources. Players may also gain additional resources by completing daily missions. Resources that a player earns will be kept in their storage and cannot be used immediately. In order to use the resources, the player must claim them from the storage. A player’s storage size is limited, and every claiming process will cost them a percentage of the resources. To minimize the claiming cost, the player can increase their storage size by purchasing NFT castles. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://castleoverlord.gitbook.io/whitepaper/getting-stronger/resources.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.