How To upgrade

[Conga Time Pyro]

hey guys i'm a complete dum dum but how do you upgrade you tiers and give them xp tickets i have like 30 xp tickets and i managered to beat the whole game by playing smart but i feel like the mirror dungeons would be easier if i had their identies at a higher teir

[artemaffbe]

->sinner, hold click. and u should see a screen with the current identitie. so u can upgrade cliking in the + and tier is just at right.