An adorable old man that entertains kids with old histories of heroes. But behind that appearance lies a powerful wizard with a hard mission.
A beautiful girl, queen of a small kingdom. She is the last descendent of the Great Tempest, the choosen of Hydros.
Perhaps those that practice elemental magic begin to take on characteristics associated with their chosen element. For instance, an earth elementalist might be prone to agoraphobia, while air and possibly fire elementalists might have problems with claustrophobia. Water elementalists might always seek the path of least resistance. A fire elementalist might have a cat's opinion of water. This could also apply to physical differences. Fire elementalists might have a freakishly high metabolism and a permanently high body temperature. Water elementalists would probably never get dehydrated, but might slow down a lot when it's cold. Etc, etc.