User blog comment:Bloobloop/It's Been an Eventful Few Days/@comment-76.121.115.220-20150915032629/@comment-26045389-20150915073354

From what I remember, they can level up the third/active skills on ur cards, which are usually leveled up by using 3* + cards, the higher the level the scroll the more they level the skills.

Also, wrrong thread to post this.