The Weird World: Magic

Magic:
"The power of influencing the course of events by using mysterious or supernatural forces."
— Magic Definition, Online Dictionary

Magic, is not an unexplained force, but rather something that has been extensively studied over the ages until in some ways, it has become another form of science.

FORMS OF MAGIC:

Abjuration
"White Magic" that consists of healing, purification, and protection spells. This includes the creation of magic armor, and force fields used for protection. Abjuration is almost strictly defence or supportive, so practitioners often aren’t skilled in combat, though many have a strict code of pacifism. It should be noted that when it comes to healing wounds, there are limits.

Alchemy
Also known as "Magical Science", Alchemy generally includes potion making, as well as magically transmuting matter into other forms and manipulating elements. It also involves the creation of golems and magical items. Among these are the Elixir of Life and the Philosopher’s Stone, both magical artifacts said to grant immortality and wealth, respectively.

Conjuration
The magic of casting spells to summon or banish spirits and creatures. Conjuration involves taking time in the creation of a magic circle to summon. The bigger the magic circle gives the bigger summon, though summoning giant beings can be mentally taxing. Making a pact with a certain being might make the conjuration easier.

Dark Arts
Knowledge demands sacrifice.
— Ancient Craving, Magic: The Gathering
"Black Magic" consisting of spells that cause pain in others or even their destruction. Users are willing to go farther than most would even consider if it serves their ends. Very, VERY illegal. Only the most depraved individual will even think of practicing this form of magic...

Divination
Magic used for predicting the future through a variety of different means and methods. Everything from needles to tea leaves can be used as a medium for telling the future. Though most need specific items to help them work.

Enchantment
Spells that can manipulate the minds & emotions of others. Some users have incredible beauty used to enchant, others can charm objects to give them magical capabilities. Generally frowned upon by most, as it’s an easily abused form of magic.

Illusion Magic
Related to Enchantment, the creation of illusion spells are used for various effects. This ranges from simply disappearing to changing one’s appearance. The really talented illusionists can create illusions with various psychosomatic effects or even illusions that are partially real.

Necromancy
"Life is temporary. Death is eternal. One who comprehends death, who makes an ally of it, can comprehend eternity... or at least, get a fair leg-up on other, squeamish mortals. The Necromancer takes the Reaper's hand and joins him in the dusty graveyards, exhuming corpses, lopping off bits of gibbet-fruit and building sculptures out of bone. Sometimes she whistles up a ghost or draws the essence of death into a living body. To master such arts, she auctions her soul to Infernal masters - demons or Spectres swimming in the Underworld. Sometimes, she even lets them enter her, channeling the spirits in her own living flesh."
— Mage: The Sorcerer's Crusade - Infernalism
Technically an offshoot of the Dark Arts, which deals with the dead. Using Necromancy is highly frowned upon, because A) It goes against the natural order, B) Anyone wishing to raise the dead will have to kill something living to make it work, and C) There is a high chance that something might go horribly wrong, leading to severe consequences…

Physis Magic
Magic calling upon the physical forces of the natural world. This usually involves controlling animals and nature, but also includes manipulating elements, controlling the weather, or even creating diseases. Naturally, control and discipline are very important in this form of magic. Physis Magic does not work in sterile environments, and pollution is very detrimental.

(Other forms)

Blood Magic:
“All power demands sacrifice and pain. The universe rewards those willing to spill their life's blood for the promise of power.”
-Sindri, Alpha Legion Sorcerer, Warhammer 40,000
Another form of magic lumped in with the Dark Arts - and for good reason. It’s a form of magic that involves using spilled blood for a variety of methods. These include binding or freeing a target, tracking others, divination, conjuration, creating portals or liquid surveillance, or just plain old manipulation of blood and its properties. Of course, getting the blood to use tends to be a major issue...

Music Magic:
A form of magic that’s rapidly growing in popularity, a user can cast spells just by making music. Spells cast in this manner have a variety of effects ranging from magical blasts to summoning to even affecting reality. All you need is an instrument (usually some form of stringed instrument) or your own voice, the knowledge and skill to use it, and some magic and you too can pull off the impossible! This type of magic is also highly regulated, as it has a high propensity to be abused for nefarious purposes.

Ofuda (Paper Charm Magic):
A form of magic performed more commonly by Japanese Onmyoji, involving the creation of paper charms and wards. The seals can create protective wards, form entities called Shikigami to aid them, or even serve as explosives. The biggest downside of Ofuda is that the spells need to be made beforehand, and a limited by the number of charms.

Sealing Magic:
Magic used to seal objects within another and release them when needed. If say, a spirit is sealed within something, it might also grant that object some form of power. Seals can also be used to bind a soul or pieces of it into something - or even someone - else.

Wyld Magic:
By tapping into the very source of magic itself, a user can gain immense magical power and the ability to reshape reality to their whims. Needless to say, this form of magic is VERY unstable, and can easily cause vast amounts of destruction, not to mention drive the user mad.

Rule #1 of Magic: There is always a price. Always. You must always make sure you know the price, or it will come back to haunt you. And it will be paid, one way or the other. The price can range from something small like the magical energy needed to cast it, your sanity, or even your life.
Magic is balance, meaning there will be consequences to offset the benefits. Casting magic takes concentration, focus and mental strength, but it will also drain one’s magical reserves and stamina.  Without the proper knowledge or magic skill, a spell will end up going wrong. And on the off-chance that a spell caster is interrupted at a crucial moment… the results can be disastrous.

There are magical-resistant substances out there, as well as ways to negate magic use. Though magic and technology is not quite as incompatible as people would think. Magitek is quite common now, but it didn't really catch on until the late 80's-early 90's. Nowadays, even non-magic users can carry around, say, magic-powered music players if they wish.