Is unlocked at level 80.
Increase 50% of growth rate additional and basic attributes after advancing once.
Increase 100% of growth rate additional and meanwhile is improved the quality of partner.
So if the spanish translate is good Tavern Uryu 380% of growth rate, and 2nd is 430%, for example.
You can't upgrade event partners or SWP partners the upgrade is purely for tavern partners that upgrades their growth rates and turns them into a red name, maybe in the future they could push the update further by allowing the old event partners whom are gold also upgrade to red name but who knows. its only for tavern partners at this point.
let gg suck moneys at vip players 100% we get free good stuff on long time, so vip always need to spend moneys on new stuff the game is infinity why is a game business