Magical Girls are manly.

Magical girl plot thus far, not sure how to explain the reasoning behind this to anyone besides kitteh but... here's what I've got so far, though it's only background at this point

Background
For centuries mankind has been safeguarded by the thirteen celestial spirits, mystical beings who have watched over the earth and prevented the dark creatures known as demons from stepping through the boundary between planes and unleashing destruction upon the earth.
Over time however relations between the spirits and mankind grew weaker. The spirits continued to protect mankind but humans began to scoff their gifted peace. With no dangers around them they took to each other's throats in bloody war, much to the distress of the spirits, but in particular the Dragon.
Unwilling to let them sink into chaos, the Celestial King rose against the humans in an attempt to subjugate them, and force them into accepting him as their ruler so he could lead them to a world of peace. To do this he selected a champion, a young woman of great potential. With the power bestowed upon her she began to change the world, but as the world began to change the boundary weakened due to the imbalanced power and the demons began to step into the world in increasingly high numbers.
Whilst his intentions were pure, the Celestial King's plan caused more suffering then good. Too stubborn to change his mind however, the Celestial King refused to halt his plan despite the pleas of the other spirits.
Eventually they were left no choice but to oppose him themselves, leading to a great confrontation that divided the spirits. In the end however the Celestial King was banished along with his champion, locked within the very plane of the demons he had fought to protect the world from.
The remaining spirits put their differences aside and peace returned to the world for a while. The demons were removed and the spirits prevented them from causing any more troubles.
Centuries past, a small time for immortal spirits, however mankind advanced tremendously and the spirits quickly became things of legend, myths forgotten by most.
Just as mankind forgot however, the demons began to break into the human world once more. For what reason was unknown. Presumably someone was calling them into the world, but who that person is or what their motives are remain a mystery.

For the past few months demons have begun appearing throughout the world, monstrous beasts bent on carnage and destruction, each unique in form and abilities. As time passed they have started appearing in increasing numbers and strength. Whilst any one could level a town, a rival force has appeared, and thus far prevented any major casualties.
Little is known to the public about these mysterious defenders as they disappear as suddenly as the appear, but they are the champions of the celestial spirits, young girls chosen by the spirits to wield their power and use it to fight the demons and send them back the their demonic realm.
Though the exact abilities vary greatly between individuals, one thing is clear, these magical girls are incredibly powerful and thus it would be a great tragedy were one to use them for evil.

The 13 spirits.

The celestial spirits are mystical beings tasked with preventing the demons from entering earth. With the exception of the Celestial King, each takes the form of a particular animal. Whilst they can't interact with the world directly, they can form pacts with young/teenage girls, giving them great powers they can use in the spirit's name. Once a pact is formed between the two they share an intricate bond, as one's power weakens so does the other's power.

Snake: Kitty
Ox: Kitty
Goat: Kitty
Tiger: Rotten
Celestial King: Rotten
Rabbit, Dragon, Monkey, Rooster, Rat, Pig, Dog, Horse: Undecided/unused.

The Demons

The demons exist in a world separated from earth, an alternate plane of endless darkness known as the negative realm. They are dangerous creatures varying wildly in form and powers, which a primal intelligence incapable of anything more then destruction.
For the most part the demons are restricted to their own world, but in rare cases they can step into the real world due to an excessive amount of negative emotions or magical energy. If one knows how, they can even summon the creatures into this world through arcane rituals.