Warrior classes have excellent hitpoints and poor mana. They are practiced with weapons, and have the strongest parry of all classes.
A warrior is basically trained to kill stuff. Almost all warrior skills are oriented towards killing an enemy. If you are a newbie, a warrior with minimal spellcasting ability is a pretty good combination.
Warriors rely on a high constitution and strength, with dexterity thrown in for good measure. Constitution gives them the high hitpoints needed in battle, while strength and dexterity are needed to master various skills.