QM's Note: I messed up with the first attempt at a Green mage quest several years ago, so this is my attempt at a new one. The following will inevitably be rather dry; since the choice of secondary mana color is going to affect the PC's personality, I'm confined to exposition until that's taken care of. It'll pick up in the second story post. Feedback would be greatly appreciated.
Over the last century, numerous religious fanatics have claimed the end of the world is imminent and would occur on a specific day. You've always known they were wrong, but not because you believed humanity would persist forever. Ragnarok is coming, just not quite as quickly as the preachers claimed. The irony of your certainty is not lost on you, but you possess something they don't: a prophec—no, wait, they thought they had that too. Well, yours is a magical prophecy instead of some vague allegedly-divine nonsense, so ha!
Two days ago, the eldritch abomination known as Walpurgisnacht devastated the Japanese city of Mitakihara, killing over ninety percent of its population. Video footage and survivor reports spread through the world like oil through water, coiling outward to grab the attention of even the most secluded shut-ins. The vast majority of humanity has absolutely no idea what they're looking at, but you know it's only a matter of time before a Magical Girl shows up on live television to explain the eye-watering footage of eldritch abominations flying through the city. Magic will become public knowledge, some poor girl will accrue a gargantuan amount of potential from the vastly increased number of coincidentally overlapping wishes, and Kyubey will use her Witch to squeeze one last burst of power from the dying Earth.
At least, that's what would happen if nobody stops him. Contributing to that effort is why you're currently moving into an apartment of your very own years ahead of schedule. The legends of your family claim that a clan friend, a Seer of Blue, learned of Kyubey's future intentions by following the cyclic patterns of his past. Earth wouldn't be the first, the second, or even the millionth world Kyubey's people had sacrificed as part of their continued energy harvesting operations. It might be the first world possessing magic the invaders hadn't granted, though, and is definitely on the shortlist of worlds that knew of his intentions.
Your immediate family is but one part of a larger clan of Green mages, or those wielding the magic of nature, instinct, interdependence, physical strength, and growth. You don't actually know where the other sections of your clan are, nor do you know where the clans of Blue, White, Red, and Black have gotten off to. You suspect many of them were killed during World War I and II, but there's no real way to prove that.
The goal of your particular family line was simple, but effective: occupy an area, dramatically improve its Green mana production, and link it to an appropriately-sized sympathetic gemstone. Individually improved creatures might be killed, but the land would persist forever, right? Right. Things were going great until humanity decided to cut down the wilds en masse, the bastards.
As the youngest child (and the black sheep) of your family, you ended up with the job nobody else wanted to tackle. Or at least, you assume it's the harder one; you don't actually know what the rest of your family is doing. Until the Day of Silver Skies arrives, you need to contact contracted Magical Girls, keep them alive, and turn them against Kyubey without letting him realize your abilities aren't the product of a wish. When the Silver Skies come, you'll need to kill the swarms of super-Familiars created by whatever eats Walpurgisnacht, eliminate the worldkiller-Witch itself, and rally your allies against Kyubey before he can make another.
Admittedly, you're not quite sure how you're supposed to get there. You can sense Witches when they're within 100-200 meters, but Magical Girls are supposed to have a range measured in kilometers. The good news is that you don't actually need the Grief Seeds you'll get from killing those particular abominations. The land and your own reserves provide your daily allowance.
Green magic lets you break weapons, objects, and enchantments. You can also infuse plants and animals with mana to increase their rate of growth or even push them beyond what their species would manage without, say, well over a thousand years of selective breeding to work with. Many of these changes persist across generations, but your family has chosen to instead work toward resistance to Green mana. Or, more accurately, lack thereof. Your innocuous young dogs, birds, and cat will not only violate the contract you signed before moving in, but can also (temporarily) grow to the size of street vehicles with a bit of Green mana to help them along. You would say "the size of buses," but the birds you have with you don't actually get that large. Yet. You once got to see a pyramid-sized puppy and you're eager to sic one on a Witch someday.
Given what humans have been doing to the environment in recent years, Green-infused plant adaptations tend to be somewhat weirder. Plants are also much more receptive to Green enhancement than even the best animals will ever be. Using your personal daily mana allowance on a dog might give you a titanic animal for all of an hour or two. Doing the same thing to a single tree seed would permanently give you multiple multi-story trees. Vines are even more fun; you could block off an entire street using meter-thick vines without even half your reserves.
The more you use Green mana, the more of it your surroundings will produce. Killing an infused being doesn't halt Green generation, just slows it down slightly; the Green released by their demise will continue to help other life grow and thrive. An entire land would have to be burned to the ground and the ashes salted before Green would be truly wasted.
Unlike the rest of your family, you also possess a second color, one they could only teach you the barest basics for. You're pretty sure that's why they ended up assigning you to outreach efforts; even if Kyubey realizes your magic is an anomaly, it'll still be hard for him to find the rest of your clan.
What is your second color of mana?
[] Black.
You aren't content with merely being one of the mages responsible for saving the world. You want to be known as the greatest mage with all the glory, influence, and wealth that would come with such a title. You're also a bit less of a goodie-two-shoes than other girls your age tend to be; you're not going to kill or torture someone just because it helps your goals, but you suspect some blackmail (heh) and threats will be helpful from time to time. If something is an effective weapon, you might as well use it. Unfortunately, you supposedly also have a tendency to treat conversation as though it's just another kind of fight; you've been told you have a tendency to subtly insult others and generally come across as somewhat cruel. You're working on that.
Witches generate Black simply by existing. As a (partial) Black mage, you can steal that power and use it for your own ends in combat—at a price, of course. The more you draw on in a short period of time, the more exhausted you become and the more susceptible you are to disease. Your resistance to these effects is slowly increasing with time, but you know better than to think you'll ever be able to steal all of Walpurgisnacht's power, let alone that of whatever will eventually cause the Day of Silver Skies.
Your direct magic seems to have been born from the wet dreams of edgelords everywhere. Spells of fear, curses of exhaustion, arrows of instantaneous death (even if yours don't work on targets larger than gophers yet), veils of darkness human eyes unconsciously try to avoid, stealing the life of others to empower yourself… really, with your apparent powerset, you wouldn't be surprised if some third-world dictators were themselves Black mages. You think sacrificing someone just for magical power would be a horrible betrayal of the goal you're fighting for, but if you do end up needing to kill someone anyway, you might as well make sure you get some extra perks out of it.
Your pets miiight be as frightening (to some) as Familiars at this point, but there's no denying their effectiveness. You've been making excellent progress with venom and think you'll be able to harm even Witches soon enough, to say nothing of their current usefulness as anti-human weapons. You also have some ideas for extra natural weapons and maybe extra armoring, but you didn't want to implement either of those under the disapproving gazes of your family. Still, if the notoriously aggressive Magical Girls decide to pick a fight with you, you can hit right back.
You can also raise the dead as Black shades, but your parents tried to ban that. You even came up with a slightly weaker version that doesn't recall/enslave souls and they still said it was off-limits! Honestly, it's like they forget what we're facing. Now that you no longer live with them, you're free to raise as many or as few undead as you want. As cool as it might be, you have to admit Magical Girls might not approve of the whole technically necromancy angle.
[] White.
You've always known your generation would be the one to endure the Day of Silver Skies, the time when Kyubey writes off Earth and prepares to move on. You've grown up well aware of the fact that everyone you'll ever know or could know will die if he isn't stopped. Your suspect this heavily affected your social development; it's always been easier for you to bond with your pets than with those who will die if your best efforts come up short. You're no longer half as morbid as you were when you were younger, but your seclusion has left you shy and unsure of how to handle social interactions more complicated than "Thank you," "You're welcome," and "Do you want any help?" At least you don't necessarily have to talk to people to defend them, and you are trying to make some human friends.
You'll have a pretty easy time pretending to be a Magical Girl. Summoned shining armor? Check. Magical weapon? Check. Resistance against curses? Check again. You can even heal people and make shields. Provided, most of those are pretty expensive and fragile at the moment, but you're positive you'll get better and uncover more abilities with more practice. If a fictional paladin, angel, or priest could do it, you suspect you'll be able to do so yourself.
The true glory of your magic lay in its interactions with your allies (even if those are just your pets right now). Enhancing three animals with a weak effect is comparable in difficulty to enhancing just yourself with with a double-strength version. Your parents have mentioned this trend will continue and even improve as you grow more skilled with White. According to them, Joan of Arc could infuse her entire army with enhanced strength, vigor, and coordination. You believe you'll eventually be able to do the same.
You think you'll be able to resurrect the recently deceased as sentient spirits, but you've never gotten permission to try it on a person. At least Aerie and Silva, your first two birds, worked pretty well as proofs of concept; both of them died almost a decade ago and their ghosts are only slightly less coherent than they were the day you pulled them back.
[] Black.
[] White.