When you reach level 10 with any character you will need to promote them to be able to level up future. Every character can be promoted up to 5 times only and after every promotion you will get an additional 10 levels to level up till you can promote your character again. Once you do the promotion your character will gain a new title and will be reset back to level one, keep in mind that this resets can not be undone.
To do a promotion go to your Garden or Graveyard and then go at the back to your stats room, choose your specific character chart and then go to promotions and select the character that you wish to promote. Characters available for promotions will be highlighted by a pointing yellow arrow.
