Multiclassing?

[JoelSammallahti]

I would handle multiclassing in the following way:

1. You start out with one class. Multiclassing happens with earned character points.

2. It costs 5 points to unlock a new class for its special abilities. (In GURPS, this would be called an Unusual Background, but that's not important. It's just a premium that discourages picking all the classes' individual cherries.)

3. Once you've unlocked a class, you need to buy all of the mandatory advantages and skills of that class before you can buy any of the optional ones. You don't need to buy your Attributes and Characteristics up to the levels on the template for your secondary class - but it makes sense to do so.

4. To gain Power Investiture or Magery, you need to complete a personal quest specified by the GM. It shouldn't be crazy difficult, but it needs to happen in-game, not during downtime. "Find the tomb of Saint Bugarak" kind of thing.