Skill Cards are used to enhance your General’s Skills. These Cards provide a higher chance of increasing your General’s skills than just using a General. These cards DO NOT unlock Skills.  

The Cards come in different tiers, that contribute to the amount of Skills that they have a chance to enhance in your general.

Skill Cards I & II increase the chances for a Skill up on the 1st or 2nd Skill of your General.
Skill Cards III & IV increase the chances for a Skill up on the 3rd or 4th Skill of your General.

Both the Card itself, and the Skills on the Card can be leveled. Increasing the level of the Skills on the Card increases the chances of enhancing your General’s Skills.