Mars

Mars. Our drive, our ambition, our engine. What propels us forward. What makes us angry. Men. Aggression, war, battle.
Mars in the natal chart shows what your sex life is like. What your sex drive is. Your "man" so to speak. Why you are so ambitious and why you are not. It can tell of abuse or where we feel squelched.
Without Mars we have no arrow pointing us in the direction we want to go. If you are unable to point your arrow because you're waiting to hear what it is you're meant to be doing, then chances are your Mars faces great challenges in your natal chart. 
A lot of lifetimes our Mars energy has been geared toward showing aggressive behavior or even murder. Because of those things that have gone on for us or someone in our family line, we clip our wings, so to speak, in this lifetime. We wanted to be sure that we were not carrying "so much" Mars. 
But that is not the correction we need. We all need a healthy Mars in order to exercise will power or even to exercise at all! When Mars is in a square aspect to other planets, in the 6th house, or at zero degrees in a sign, he has no charge. His energy is then expressed by misdirected anger. Even rage.
Mars holds the key to taking you from the place you are, to where you want to be.