They are the keeper of the keys, the true possessors of infallible knowledge and wisdom. Tragically, zealots have convictions about beliefs and behaviors but rarely about attitudes. Zealots know of no such attitudes and, consequently, often tear down more good people and institutions then their enemies have. Interestingly, zealots often come to their beliefs through emotional crisis or cultural conditioning, not by careful study. It is not that they have been won over on an intellectual level, but more by an intuition by which they believed this movement and its ideology and leaders was their hope of salvation.
Zealots glorify their movement, leaders and ideology beyond all reality.
Moreover, they demonize all people who are not a part of the glory that is their movement or cause. Well, that is not quite accurate. You are a potential friend as long as you have yet to be evangelized. Once you disagree with any part of the message, then you are demonized. My experience of zealots is that they are often more motivated by self-hate then by a vision they believe in.