Skill number and level limit decided by player's rarity:

C: Unable to master skills.

B: Master 1 skill, skill can be upgraded to level 2.

A: Master 2 skills, skills can be upgraded to level 4.

S: Master 3 skills, skills can be upgraded to level 6.

SS: Master 4 skills, skills can be upgraded to level 8.

SSS: Master 5 skills, skills can be upgraded to level 10.

When a player wants to learn a new skill, replace a skill, or upgrade a skill, he needs to consume players with the skills you want to learn or upgrade.The level of that skill is calculated according to the sum of the skill's level of the original player and the material player.

For example,you can upgrade a player‘s level 3 "Cannon" to level 5 "Cannon" after consuming any players who master level 2 "Cannon".