> For the complete documentation index, see [llms.txt](https://whitepaper.kingdomheroeswar.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whitepaper.kingdomheroeswar.io/game-overview/growth/skill.md).

# Skill

Each hero can learn and upgrade 4 skills according to its grade. The first skill is the Active skill, which can be used directly by the player during the battle. The other 3 skills are mainly passive skills or skills that are activated automatically during battle.

<figure><img src="https://1882394756-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FTiiG12E1BCpkapIsef5W%2Fuploads%2FFjOiTUSZX6q89wBNxmxF%2Fweb3_skillup.png?alt=media&amp;token=2ae89003-0b60-4c63-8311-a48c746d4665" alt=""><figcaption></figcaption></figure>

Players can combine heroes to form a deck that can activate a chain skill. When a chain skill is activated, it can cause strong damage to the enemy.