Red
Red is one of the five colors of mana in Magic. It is drawn from the mountains and embodies the principles of impulse and chaos. On the Color Pie, it is allied with black and green, and is enemies with white and blue.
Philosophy
Red looks on the world and sees adventure. Life is a chance to experience something - many things - and for Red, there is no more worthwhile endeavor than to enjoy life by the adventure it offers. Experiences are what life is about, and to appreciate the full range of life's experiences, Red lives by emotion. What makes one laugh, what makes one cry, what one hates and what one loves, these make up what person is. A person can look only to these, believes Red, to find one's wishes and desires in life. Deny these, and life is meaningless.
To accord with its beliefs, Red seeks out new experiences, and new ways to express itself, and seizes on them. It finds these ends in the complementary pillars of Impulse and Chaos. Impulse, to Red, means emotional action. By acting (doing) as one's heart desires, one can only find happiness with the experience one has to show for it. With Chaos - random action - Red creates the freedom for any one to express his or her emotions. In a sense, by opening up new possibilities, Red's Chaos frees novel experiences from the "lattice" of the status quo.
In valuing emotion and adventure so greatly, what Red truly prizes is freedom. To live life the Red way - passionately and imminently - Red must be able to act on its impulses, doing what it feels each moment without delay. It doesn't want to be censored or controlled, because when one's passions are shackled from action, a person cannot be who he is. To disallow him to be who he is, is to destroy him; in Red's view, censorship is death. As such, the idea of rules, of pinning someone to one course even if his emotions urge him down another, is atrocious to Red. Where Red can see, those who dare to speak of rules and limits will meet with a furious ultimatum to shut up. Red will fight against anyone who restrains anyone else, and the tools that Red uses to make this point, and those it uses to seek its own richness of passion, are the basis of card design for Red.
Flavor
Red is the color of emotion, impulse, and action. Red sees things in terms of doing, not thinking, and would sooner act now than wait and think about its actions. Red likes to do things as quickly and with as much power as possible, heedless of danger or complication. In its own eyes, its actions are unrestricted and free.
To that end, Red cares little for slowness or control; it would rather just do. Red employs damage, and emphasizes damage through direct means, much greater than by creatures, and far greater than "technical" spells. Red opposes White because White begets the control that Red spurns. Red opposes Blue because Blue's rejection of the "irrational" in its systematically rational approach to life is in direct opposition to Red's highest esteem of emotion (this is the objective against the subjective). At best, Red is independent and free-spoken. At worst, it is dangerous and rash.
Red mages take their most devastating actions when are challenged at the core of their philosophy. Red is the range of personalities that will not travel to the mountain, they let the mountain travel to them (Explosively!). Anything standing in the way of Red will face at least as much destruction as is necessary to blow the obstacle away. When Red meets Red, the flames get high!
Rules
Red is the color that has the most direct damage (e.g. Lightning Bolt and Fireball) and is often used in aggressive decks. Red creatures often feature high power and an emphasis on "damage" abilities like haste or double strike, at the cost of durability. Red is arguably the fastest color on its own, owing to its single-minded focus on getting what it wants to and nothing more. The creature types Goblin and Ogre are primarily red, and several decks based on Goblins have been created.
Mechanics
Card Drawing
Like other colors, red has a few cards that allow you to draw more cards, but always at the price of discarding the cards you already have in hand, since red is impulsive and throws away what it has in favor of something new. Wheel of Fortune and Sensation Gorger are examples of this side of red.
Combat
As the primary martial color along with white, red receives a number of abilities that help it dominate the battlefield. First strike and double strike represent red's speed in a fight with cards like Anaba Bodyguard and Ridgeline Raptor. Flanking, on the other hand, reflects red's skill and prowess with cards such as Agility. Though the majority of creatures with trample are green, it fits well with red's beat-'em-up philosophy as seen on such cards as Sunrise Sovereign and Orgg. Likewise, rampage, as seen on Ærathi Berserker and Frost Giant, displays red's focus on rage and blind aggression.
Direct Damage
Red, angry and impulsive, strikes down any opponent with spells and abilities dealing targeted and global damage (such as Shock and Pyroclasm respectively). Along with blue, red invests in magical power with instants and sorceries, especially the latter, but where blue's magic comes from careful study, red casts spells fueled by raw emotion. Originally, blue was the premier color for creatures that can tap to deal direct damage, but this ability eventually moved to red (note the change from Prodigal Sorcerer to Prodigal Pyromancer, for instance).
Haste
Red's aggression pushes it to move quickly, and as such many of red's creatures can attack and activate the turn they enter play. Cards like Raging Goblin and Fervor show off this side of red.
Mana Production
Like its ally green, red can produce mana to speed up its spells, but its shortsightedness leads it to throw away resources that could be used better in the long run for a larger boost in the short run. This ability was originally found in black but was later moved to red, with cards like Seething Song taking the place of Dark Ritual. Other red mana producers include Skirk Prospector and Grinning Ignus.
Randomness
Red's blind passion can hurt itself and others indiscriminately. This is reflected in cards dealing with coin flips (Mana Clash) and random card discard (Gamble).