Legends of Belariath

Multi-Classing

Combat

When one takes the second class one needs to know what armor types and what weapon types one can use of those two classes. For this it's that one takes the best weapon type of the two and takes the worst armor type of the two. So for example a knight/cleric, would get the best weapons of a knight, thus being class D weapons, but get's the cleric armor limit of class B armors.

The exception to this basic rule is that racial and advanced class can overrule this. For example a seductress/knight would still be limited to the seductress weapons as that is a specific penalty of the seductress class. And a Chirot Knight, although permitted A, B, C and D class armour would be limited by the strictures of the Chirot race.

Magic

The evolution of a class into an advanced class symbolizes the specilization of the character in most aspects, They are no longer studying the broad knowledge of the Arcana as a mage, For example, but rather specifically focusing on the element fire, and what it can do. That doesn't necessarily mean that their knowledge of the Arcana dissapeares (able to keep existing spells) or even that through use of those spells they know, they might become stronger (buying slots for spells they already know) but they won't have the time to focus on learning new Arcana spells, since they are focused on learning Fire spells (can't get new spells from arcana).