Mars has just recently moved into Scorpio, the sign of its nocturnal domain. Although Mars in Scorpio expresses itself in a much more covert way than it does in Aries where his inclinations to act upon his desires are most obvious, he is very much at home in the sign of the Scorpion.
Aries is a hot dry cardinal sign in which planets express themselves with little constraint. Compare this with Scorpio, a cold moist fixed sign, where planets must bide time and revenge is best served cold. In Scorpio planets, which represent people, explore the full extent of their feelings before acting.
In transiting from Libra, the sign in which he is constrained by diplomatic niceties and romantic compromise, he is once again at home; again a fighter, a warrior, someone who will take up arms to fight injustice. He is also in his alternative element, water, symbolized by the wild tempestuous seas which we recognize in the French and Italian translations of la mer and iI mare. The word mer and mare are both derived from the word Mars.
In his transition from Libra to Scorpio he rises from the bed of pleasure to pick up his arms and go back to the good fight. Mars needs to be Mars.
In Scorpio Mars is the general who plots strategies, works undercover with intense focus, and plays the long game of entrapping and slaying his enemy.
In this transition the clear distinction between a planet in detriment and a planet in rulership (dignity) becomes obvious. Dignity and detriment represent the contrasting capacities of a planet to act according to its nature.
The dignities are created by the Sun in its rulership of Leo where it is so at home in the hot northern summer. His beloved, the Moon, is awarded a seat on his left in Cancer. And from there the other dignities, including Mars as ruler of Aries and Scorpio, are distributed.