Multi-classing is the mixing of two classes together into one character. There are only five classes in Elemental D6, but there are still options for mixing these classes. Persons with the ability to manipulate more than one element are extremely rare, and their exploits often become the stuff of legends. Consult with your game master before multi-classing to elements

You can, however, always mix the martial class with any of the four elemental classes. When mixing two classes you would take a second class when leveling up. Your GM may require some event in your character's adventure's to unlock that skill if it is a second element, though no such event is required to mix the martial class with another element

When taking a level in another class, you take the level bonuses, skill bonuses, and talent points according to the level in your new class, starting at level one. You do not get additional bonuses associated with starting a character, your first level in a new class is treated as any other level in that regard

Example
You have 4 levels in hydromancer and you level up to level 5. Instead of becoming a level 5 hydromancer, you put the level into the martial class. You gain the bonuses associated with the first level of the martial class, instead of the hydromancer class). You do not gain the hit points associated with level 1 characters of your race

Level Requirements
If a any talent, skill, or feat has a level requirement, use your total character level for this requirement