Mars represents the desire for action and physical energy.
Mars in Leo
Combative strength. He always realizes his schemes. Can undertake big projects, conclude them successfully and receive the deserved rewards. He likes responsibilities and difficulties above all, and imposes himself forcefully.
Weaknesses: Combative force can lead to violence if he thinks it necessary. He is bold, presumptuous, intrepid: he likes to face danger and can naturally have a few hiccups on the way.
Mars in IV
Quick decisions, he has a lot of things on his plate and wants to climb the social ladder. He will succeed through phenomenal work-rate. Stormy family life, where his aggressiveness shows itself.
-16 Square Sun - Mars
He is violent, impulsive. He throws himself headlong into situations without ever thinking of the consequences of his actions. This can cause a lot of problems. He cannot stand still and channels badly the energy which he possesses.
-18 Opposition Mars - Jupiter
He refuses to accept any guidance. He lacks forethought, acts impulsively and sometimes imprudently, which can cause problems. He wants everything yesterday and uses whatever means necessary to achieve his objectives, even if they are dishonest or not very commendable. His emotional life is fraught with quarrels and sometimes violent conflicts.