Skill

Skills are the second main source of the players damage (first being the Basic Attack). The player can aquire those skills by simply equipping at least one of the four weapons (Sword, Daggers, Staff or bow). Each weapon has a set of four skills which is one dash ability and 3 main ability. Each skill has 2 versions and each version has 4 Skill Rune slots for the player to unlock. Detailed version of Skill Rune slots can be found on Skill Runes  page.

Upgrading skills
If players want to keep up with the difficulty of the stages it is crucial to upgrade your skills. As for the currency that is used for upgrading the player's skill is called Skill Upgrade Stones. Since August 8th 2022, max skill level is 999. It would take around 500 million skill stones to upgrade one skill from level 1 to 999.

Version 1 skills
It's the players base weapon skill type. Version 1 skills can only be upgraded from level 1 to level 50. Version 1 skills at level 50 + 10 (cemetery)

Version 2 skills
Version 2 Skills are the stronger version of the player's base weapon skills. Version 2 skills can be acquired if the player uses the corresponding number of equipped/active Weapon's Monster Cards. More detail on cards can be found on A quick guide to Monster Cards page. Version 2 skills can be upgraded up from level 50 to level 100 Version 2 skills at level 100 + 10 (cemetery)

Credit: Purtily