Board Thread:Questions and Answers/@comment-7467815-20130506124256/@comment-6740992-20130508234912

If you use other daemons with the same skill then yes it will. But unlike the magatama which each magatama increases the level by 1, daemons might need 2-3 or more to increase the level by 1. Unfortunately there is no magatama for Yagyu and Chiyome, so thier skill will have to max out at level 15.