Of all the gacha games I've played, this game's hero upgrading system is the worst. It's so hard to earn fodders, and each requirement for upgrading to the next star is insane; the summoner's skills when reaching the 7th or 8th star still doesn't change. The campaign is very difficult. This game is dying anyway. Only few p2w players left due to devs poor game bug fixes. Don't wast your time here.