Game need possibility to transform 5 cards to NEXT grade when they upgraded to max. For example, 5 commom cards with 3 stars transformed to 1 rare card. 5 rare with 4 stars - to epic, ets.
QuinaRose Not true. I beat the ghosts with fairies. Just with spell "protection" and few upgrades to +10% attack and +10% to defence. And even without this spell as experiment.
 "IDLE Royal Fortress"){kind=icon}
 "Flash's Bounty"){kind=icon}
 "The Perfect Tower"){kind=icon}