Bottled Sun-Fire

Bottled Sun-Fire, that's the ticket.

This potion puts a stopper on a conjuration spell, your specialty, which summons a bit of the plasma from the sun, creating an enormous explosion, but more to the point bathing the area in sunlight for a second.

Who are you going to meet that you would need a flash of sunlight?

Why, a vampire, of course!

Vampires are a remnant from the elder days of the earth, when the various kinds of demon and spirit walked brazenly beneath the moon and stars and made deals freely with human beings, and stranger things. Those who became the progenitors of vampire kind were men and women who incautiously bargained for 'Eternal Youth' instead of longer lives. The ageing process can be paused, or slowed, or with sufficient power made to flow backwards for a time, but it cannot be STOPPED, that is one of the Laws of Magic. Thus the only way to grant 'Eternal Youth' is to have the person die, and yet retain a semblance of life: but it is a stolen life, a false life, and fraught with weaknesses: chief among which is that the touch of direct sunlight has two deleterious effects upon them:
1: it burns them like an open flame wherever it touches their flesh.
2: it renders them blind until the same time the next day.

Now when the texts say 'like an open flame' you are aware, as many the incautious hunter is not, that it does not refer to a bonfire or hot coals, but more a candle, which for the duration that this potion would produce sunlight is almost meaningless: however, that second effect, THAT is valuable. Against an elder it might not do much, they have long ago learned to perceive the world with other senses at need, but an elder would know better than to try to ambush you, or do anything else stupid, EXPECTING you to have some such remedy to hand, and there are not that many elders left anyway.

When True Magic returned to the world, like with the mages that had slept away the years vampires returned with it, and they wasted no time propagating their kind, turning night watchmen, 3rd shift police, and others whom it would surprise no one that they shunned the daylight hours. However thanks to Hollywood and the internet as they were uncovered the data about their true weaknesses spread rapidly, and many elders fell to the powers of the new 'Supers' some of whom had abilities like projecting laser blasts of concentrated sunlight which did more to the vampires than even normal sunlight could. The elders, arrogant in their blood fueled powers and command of many enslaved underlings, bore the brunt of these purges dis-proportionality heavily, and of the hundreds who emerged in 2001 only 20 that you know of yet 'live', though others might have gone to ground and not resurfaced.

Still, the vampires are far from extinct, much as the roman catholic church and others wishes this were otherwise. With all it takes to create a new vampire being a human mostly drained of blood and a few teaspoons of another vampire's blood, their numbers are far from diminished enough to threaten them with total cessation. Some vampires now even work as nighttime EMTs, feeding themselves on 'expired' blood from the hospital blood bank, and offering another option for accident and shooting victims who have lost too much blood and are bleeding out too fast for the paramedics to get them to an ER before they expire: since the process of 'turning' heals all present wounds and restores your youth.

That too is another source of fresh recruits, though illegal, the vast herds of 'boomers' now dealing with the ravages of old age. When you are pushing 70 and sick all the time, the prospect of 'Eternal Youth' sounds very tempting, as it did to the first vampires so very long ago: yet, as they did, the new converts often find it is a trap. Never seeing a sunrise or sunset, or even mere daylight: consuming only blood, all other tastes denied you: being physically repelled by any person possessed of true FAITH in a higher power*, of which there is generally at least one in every congregation, (though not always the pastor, priestess, shaman, or cleric), and thus denied the surcease of a faith based community, assuming any would have you in the first place: never again being able to sleep and thus dream: even such trivialities as not being able to bear children of their own body drive many who thought this to be a 'new lease on life' to seek absolution for their sin in the blazing embrace of dawn.
*(The Cross, Pentacle, Star of David, Crescent, Ohm, Hammer and Sickle, or other symbol is nothing but a focus to shore up the belief of the devout but weak willed, it is the FAITH itself that forcibly pushes the vampire back. [Yes, for this purpose 'The Communist Ideal' works as a higher power, much to the horror of clergy everywhere, though it came as no surprise to the U.F.P. delegation.])

However, while the vampires are at no risk of extinction, they are not what they once were. It is not true that the blood of the vampires thins with each generation they are removed from their progenitor, but it appears that way by comparison, because as vampires grow older they learn greater and greater command of the blood based magics gifted them by their un-dying and un-living status, so an elder of 500 years is like unto a demi-god compared to one just 'embraced' and those of 2000 years rival the greatest of supers, save their inherent weaknesses.

This is why you are glad you liaise with a pack of relative neophytes tonight, while they are young and unpredictable they are not the terror that the mysterious 'Armand' who controls the vampire community of 'Millennium' is said to be, and should, if things go south, be easily subdued by the Sun-Fire potion.

For 45 minutes you sing softly and slowly wave your hands about in specific gestures to control and summon the power into the brewing potion, pausing at set moments to adjust the flames, add more ingredients, and so on to keep the gathering forces steady, but at last you utter the final syllable and...