Lore & Background
Legends all agree that Allomancy was created with the rise of the mists, but in fact, the conventional wisdom says that the Lord Ruler gave his friends and those who supported him the power of Allomancy. These Allomancers became the foundation of the nobility. The power of Allomancy is hereditary, so even after a thousand years, the nobility still become Allomancers. The Lord Ruler and his Steel Ministry go through a great deal of effort trying to keep Allomancy exclusively in the nobility.
There used to be only Mistborn, the Allomancers who could use all the Allomantic metals. Nowadays, the power of Allomancy is weaker, and there are Allomancers called "Mistings", who can only use a single metal.
Allomancers use their powers by ingesting the correct metals, which they utilize to perform great feats.
Terminology
Allomancy is a genetic trait, but even if one has a good heritage, one must go through intense trauma to awaken the ability. This traumatic event is known as
Snapping. Typically, Snapping occurs through exteme pain, but it has happened with other intense emotions as well, like joy, though that is far less common. It's said that the stronger an Allomancer is, the more traumatic the event needs to be in order to Snap.
When an Allomancer activates the metal they have ingested, this is known as
burning the metal. Allomancers can adjust the rate their metals burn, and when they increase the rate of burning, this is called
flaring metals. However, flaring metals causes them to run out more quickly. When an Allomancer stops burning their metals, this known as
extinguishing metals.
Allomantic Properties of Metals
There are eight base metals, each in groups of four: Physical metals and Mental metals. In addition, metals are either external or internal, and Pushing or Pulling. There are two high metals, gold and atium, which supposedly only Mistborn can burn.
Physical Metals

1. Iron -
Lurchers
A Misting who burns iron (a Lurcher) immediately sees blue lines pointing towards sources of metal. Then, the Allomancer can Pull on those metals, and they will fly directly towards the Lurcher. If the object is heavier than you, Pulling that metal cannot bring that metal towards you; instead, you will be Pulled towards it. Lurchers cannot Pull on metal in someone's body. Typically in a squad of Allomancers, a Lurcher defends their companions from flying metal, and thus usually wear a wooden shield.

2. Steel -
Coinshot
A Coinshot who burns steel sees blue lines pointing towards sources of metal. In addition, the Allomancer can Push on those metals. This makes coins an easy weapon, as they are light. When objects weigh more than the Allomancer or the metal object is against something that can't be Pushed further (such as the ground), Pushing will force the Allomancer backwards. Coinshots cannot Push on metal in someone's body. Typically in a squad of Allomancers, Coinshots are offensive weapons, shooting coins at their opponents.

3. Tin -
Tineye
An Allomancer burning tin has all their senses enhanced. In addition, the mists appear more translucent to them. Tineyes are typically used as scouts or lookouts.

4. Pewter -
Pewterarm (Thug)
Burning pewter enhances physical strength. While burning pewter, the Thug is able to continue fighting after receiving wounds that kill or incapacitate a normal person, though if their pewter runs out, they will likely die. Pewter burns the quickest of all Allomantic metals, so it is important to keep supplied with it. Pewter also grants greatly enhanced balance. This can allow a Thug to perform a "pewter drag"--flaring pewter so much in order to run with immense speed for long periods of time--though the Allomancer's body afterwards will be in a state of near exhaustion. Thugs, as their name suggests, provide the muscle in a squad of Allomancers.
Mental Metals

5. Zinc -
Rioter
An Allomancer burning zinc can Pull on other peoples' emotions, Rioting them and making the emotions more intense. Rioters may select one emotion or many of them, and can also Riot many people at once, though it is challenging. However, a Rioter cannot Pull on his or her own emotions.

6. Brass -
Soother
An Allomancer burning brass can Push on other peoples' emotions, dampening them. Soothers may select one emotion or many of them, and can also Soothe many people at once, though it is more challenging. A Soother can get a similar effect as Rioting by Soothing away all unnecessary emotions except the one that is to remain dominant. However, a Soother cannot Push on his or her own emotions.

7. Copper -
Coppercloud (Smoker)
Burning copper hides Allomancy from others. A Smoker creates a
coppercloud, which is an area where the Allomancy is hidden. In addition, Smokers burning copper are immune to emotional Allomancy, though other people in the coppercloud do not gain that immunity as well. Copper burns the most slowly of all Allomantic metals, so it can be burned virtually all the time.

8. Bronze -
Seeker
An Allomancer burning bronze can sense the use of Allomancy in the nearby area. Seekers do this by listening to the "Allomantic pulses", or bronzepulses, that other Allomancers give off. With practice, a Seeker can determine the location of the other Allomancer, which metal the other Allomancer is burning, and the rate at which the Allomancer is burning it.
High Metals

9. Gold
Gold allows an Allomancer to see what they might have been if they had made different choices in the past. The illusion gold causes appears as a faint shadow, which the Allomancer can touch. It is rarely used due to possible emotional trauma.
http://www.17thshard...etals/atium.png 10. Atium
A Mistborn burning atium can see a few moments into the future, and enhances the Allomancer's ability to accept and process this additional information. This ability makes atium the most powerful of the Allomantic metals, for a Mistborn will be able to see precisely what their opponents would do, making them invincible. However, atium burns the most quickly of all metals. To counter atium, an enemy Mistborn must also be burning atium. This shows you what the other person will do, but knowing that will change what you do, which will change what the other person will do, and so forth, effectively canceling out the benefit of atium.
This is what people know of the high metals in the current time, but in fact there are Mistings of these types as well, though most are undiscovered. Since the Lord Ruler obfuscated that fact, it's believed only Mistborn can burn the high metals.
Special Allomancers: Savants
When an Allomancer flares metals continuously for a long period of time, the Allomancer actually transforms their physiology. With most metals, the effect is slight. Seekers often become savants without knowing it. Tin savants gain an incredible amount of sensory information. Iron and steel savants can sense more subtle sources of metal within the body, as Inquisitors do.
Becoming a savant does not turn an Allomancer like the Lord Ruler or some kind of god. It won't make an Allomancer into one as strong as those early who existed in the early Final Empire. Allomantic power is a different quality entirely. For those who are incredibly strong with Allomancy, like the Lord Ruler, certain rules in Allomancy are not so rigid. Copperclouds can be pierced, and metals can be manipulated inside someone's body