Multiclassing?

[Bruno]

Some things do work well together - the biggest thing to look for is a attribute synergy, and then advantage synergy.
Knight/Swashbuckler has so much overlap that it's a little tricky calling that blend multiclassing - but certainly workable.
A good one is Swashbuckler and Thief, with both of them focusing so much on high DX and DX based skills that they have a heavy concentration in the same area.
Other good blends are two spellcasters, like druids and wizards - both heavily IQ based, boths mundane skills are knowledge oriented, both benefit from having a pile of FP (but the two spell types can't share ER, remember).

A lighter weight version than fully blending two templates is to take some of your optional advantage points and buy some skills or advantages from the other. Swashbucklers have a lot of points in optional advantages - you could take some of those points and spend them on DX-based "criminal" skills from the Thief template and make a character that is still good at thief things - perhaps not fantastic because you have some IQ-based holes in your portfolio, but still good. You could use your Quirk points to pick up some of those IQ skills too - better with one point in each than at default, even if your skills won't be super great.

Another (probably safer) way to "multiclass" is to pick your "second class" and spend your earned character points as if you belong to that class - either instead of or in addition to your own. In my game, I would require you to pick-and-stick to your second class for 25-50 character points before I let you buy freely from both templates, just to prevent "dipping" for the shiniest thing.

[mlangsdorf]

I've actually played a Cleric-Mage in a DF game and I actually don't recommend multi-classing between two spellcasters. You end up buying Magery/Power Investiture twice, so you're paying 60 points but not getting ridiculous skill levels.

You have a lot of different spells that you can potentially cast at any time, but you can only cast 1 spell per maneuver. Pure wizards or clerics generally have more spells than they points for, so adding more options doesn't gain you anything. You either have 2 ERs that are half as efficient, or no ER and then you recover fatigue slower than a wizard PC and a cleric PC would.

In general, I wasn't sad when that character died and I got replace him with something better.

I do agree that knights and swashbucklers make good starting points for multi-classing. They're both perfectly good at their roles without spending any of their 60 advantage points, so spending 50-60 points to do something else isn't terrible. The downside is they're IQ 10 at the start, so it's hard to turn them into effective spellcasters while only spending 50-60 pts.

[malloyd]

Originally Posted by mlangsdorf

I've actually played a Cleric-Mage in a DF game and I actually don't recommend multi-classing between two spellcasters. You end up buying Magery/Power Investiture twice, so you're paying 60 points but not getting ridiculous skill levels.

Mind you if you just wanted access to some of the *non*-spellcasting traits on the other template, that might be an interesting character concept. I'd probably let you have that for just a plausible backstory. You might be a cleric of the God of Magical Scholarship, or a particularly pious wizard, or one who studied medicine for a couple years.

[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.