Classess and levels question

[Lion King]

So what is the max level? Cause i'm past level 12 but wanted to hold off on promoting to another class just in case some classes have stat requirements. In the guide section, they mention the protag female being able to unlock certain classes with low purity and high corruption pertaining to erotic class/skills.

And on that note, once we promote, can we change to the other option we didn't previously pick? Like if i went mercenary with the main guy can i switch back to Gladiator? I created a save and promoted to see what would happen and i see that i can use the item once more so i guess there is a tier 3 promotion as well?

[Ratattata]

The max level is 20 and you can't swap. Each character can promote twice except for Vivian and Cythraul.