Normally when one hears about Mars, they will get a fear. Mars is presented in such a way that we get a feel wherever it is present, it will ruin all the features of that house. Manglik dosha is an example of this is Martian fear.
In ancient texts, Mars is shown as the son of Earth and Vishnu. Different texts speak different stories. In all astrology branches, whether it is Vedic or Babylonian, Mars is considered as the planet of War and passion. Mars represents brother and co-born, aggressiveness, aggression, land, property, military people, engineers and surgeons, rulers, accidents, war, ambition, strength, and conflicts. Mars rules Aries and Scorpio. It is exalted in Capricorn and debilitated in Cancer. The Sun, the Moon and the Jupiter are his friends, whereas Mercury and Ketu are his enemies, Rahu and Saturn are neutral to Mars.
Since Mars is a form of intense energy, the house which Mars is placed shows struggles. You need to be very careful in the matters allotted to that house. Mars is named after the Roman God of war. Ancient astrology always describes Mars as a malefic planet, but a life without valour and vigour will be terrible. Mars symbolizes that valour and vigour which we need to fight against the odds of life. According to the placement of Mars, we can understand whether our vigour and valour are directing us into the righteous or unrighteous way of life.
It is very easy to understand how Mars is going to influence you. Mars, since it is a soldier planet, it likes to be in the front of your life, defending you and promoting you. So, Mars should place in a house where it had a deal with others. If it is not in a house where it has to deal with others in a direct manner, then your Mars is going to be a bad boy in a double dose.
For example, Mars is exalted in Capricorn, it is highly forceful if it is in the 10th house too. So, for Aries Ascendant, if Mars is in Capricorn, Mars will be in the 10th house. The 10th house represents profession, career, promotion, power, fame, honour, status, karma in life, character, authority, government, and bosses. The placement for Mars in 10th house for Aries ascendant doesn’t say that this will easily get everything mentioned in the 10th house. The meaning is that the person is highly ambitious and will do anything for success.
If Mars is in a neutral sign or in the sign of enemies, then the amount of willpower can vary and you have to make necessary adjustments or realizations. Astrology is not used to get what all you wanted in your life. Not everyone can’t be an allrounder in a cricket team. You may not get all the comforts you want in life. You have destined for certain losses also.
Why Mars is debilitated in the 4th house and in Cancer because this house is dealing with private matters. The soldier is to deal with outside world. So, Mars will be very much irritated in this house. If it is in Cancer sign, and in 4th house, such placement will happen only in case of an Aries Ascendant.