(EDIT: Re-clarified and modified information based on blizzplanet's information, which seems to grab most of the lore information from the WoW RPG books.)
As a rule of thumb, it's generally required to know a little bit about the race you play in order to adequately roleplay. This is achieved by doing a little bit of research into the lore of gnomes in the World of Warcraft. By doing so, you would know what an appropriate age your character has to be, and to have the appropriate backstory that fits both the age of your character and the timeline of events in the Warcraft story. As a beginning roleplayer of the gnome class, I researched a few sites that detail the lore behind the gnomes of WoW in an attempt to try and solidify a backstory for Wimzig. Two sites in particular, wowwiki and wowroleplay provide a good start with regards to that, and I would be more than happy to share a bit of my findings with the rest of the blogging community.
Gnomes have had relatively recent debuts in the historical records in the World of Warcraft. According to Wowwiki, the earliest historically recorded contact with gnomes was with a Dwarf, occurring 200 years pre-BC. After continuous interaction between the two races, an alliance grew, resulting in the construction of Gnomeregan, a bustling techno-city nestled deep within the mountains of Dun Morogh, close to Ironforge. They served as allies to the Bronzebeard clan of Dwarves during the dwarven civil war known as the War of the Three Hammers. If you have a character that is approximately 100-200 years old, you may be a veteran of that war, having participated in that war, serving under King Bronzebeard.
During the Second War, the gnomes of Gnomeregan were enlisted to help the Alliance due to their talents in engineering and technology. If you're a Gnomish engineer of 100-200 years, you may have participated in such technological assistance. You may have been a pilot of flying machines, sent on scout missions during the second war, or perhaps a nautical operator of a gnomish submarine.
The Third war marked a significant change to the Gnomeregan gnomes. Their city was invaded by the Troggs, who mysteriously appeared after the unearthing of ancient Uldaman. According to blizzplanet, High Tinker Mekkatorque, the current racial leader of the Gnomeregan Exiles, ordered that the radiation valves be opened from within the city, in an attempt to ward off the troggs. It worked temporarily, but the troggs were not the only ones affected. Numerous gnomes were stricken with radiation, and as a result, the surviving population of Gnomeregan fled to live in Ironforge with their dwarven allies. If your character currently lives in Ironforge, you are a refugee from the city of Gnomeregan, and your relatives may have died during the ivnvasion and defense, or may have been converted by the radiation into leper gnomes. Perhaps your character may be tinkering around with alchemy and/or first aid to look for a cure for their leprosy.
Generally, the life span of gnomes range in the several of hundreds. Warcraft gnomes reach their "coming of age" phase in their forties and fifties, become middle-aged at around 100 years old, and will live to around two hundred on average. Well-versed heroes of gnomekind can live to up to twice as long, but will be of only symbolic importance at such an old age, meaning that if you can't be 300 years old and out slaying 10-20 beasts at once, unless some sort of magical effect was involved (hooray for mages and warlocks!) to extend your lifespan, preferably at the cost of something important (sanity most likely).
At birth, gnomes are given a first name by their parents, and their last names will initially be that of an important person their lineage. As they come of age, they will either earn a last name from a social group overlooking gnome society based on their accomplishments, or will have invented a name for themselves. Depending on your character's specific age, you may have already been given a last name, or still carry the last name of an ancestor and are literally making a name for yourself.
Gnome families tend to be small and close-knit, simply due to their priorities placed on R&D, as well as their long lifespans. As such, they are normally either the only child, or have only one sibling (two is probably pushing it). Due to the lifespan of gnomes, the offspring of a gnomish father might stay with the family for up to 30 or 40 years, until he or she is deemed of age, and will be given the opportunity to explore him or herself and discover their "calling" in life. Due to this timespan of social proximity to the parents, combined with the common occurrence of "only child" gnomes, parents themselves are often overprotective of their children.
The reason why the gnomish race is technologically superior to nearly all other earthly races is because of their high intellect, creativity, and curiosity. Generally, they are good-natured and down-to-earth, and get along well with different people. They are generally introverted as a society, but are willing to accept aid in exchange for their coveted skill sets. This is especially true in regards to their situation with Gnomeregan.
As a result of of all this, gnomes tend to be quite self-centered. Their curiosity knows no bounds, and they will continue along the same line of thinking no matter what the cost, often resulting in cases of tunnel vision. Such self-centeredness combined with their intelligence causes gnomes to also be quite cunning in nature. Likewise, it is faulty to think that all gnomes are absolutely good-natured; if you happen to cross one the wrong way, do not expect much mercy. Perhaps it is because of their outwardly good nature that they are overlooked as possible vessels of pure unadulterated evil. Either way, a gnome is aware of the way they are viewed, and use this as a means of deception, striking fear when the enemy least expects it, if at all. This is why gnomes make excellent rogues.
Gnomes are neither political or religious in nature. They do not heavily rely on the leadership of a monarchy, not having any concrete lineage in several centuries. Instead, an elected council leader is given the position of High Tinker (such as Mekkatorque, who is the current political leader). The title of High Tinker, however, is more reflective of their technological accomplishments, rather than political savy. As such, society simply relies on overall common sense governing, and will obey such laws to simply establish peace with each other and their allies, as they have with the Ironforge Dwarves. Due to their ways of thinking, gnomes keep themselves grounded and attached to the material, and are thus not reliant on any forms of religion; they get by on their own strength and on the solidarity of fellow gnomes.
In my opinion, gnomes are a truly neutral race with regards to alignment. Their origins prior to the events of Warcraft signify that they simply keep to themselves, and have no allegiance to morality or immorality, but rather the material. That is not to say that they are incapable of being either. Their adherence to law is minimal, they just do enough to get by and make themselves sure that they don't fall out of any sort of order, as it goes against their social progress, symbolically and emotionally represented by the technology they create. If anything, they're more attentive of the natural laws of science rather than society.
Arcane energy is something of a wild phenomena in the scientific world seen by gnomes. Having lived for centuries under the worldly assumptions of matter and energy, Arcane magics are a marvel for being capable of warping the laws of regular physics. As such, gnomes view the learning of arcane magics with the same approach as they do with science. They research the nature of the arcane, and how to harness it by first understanding the laws of science, so that they know how to break it. While other mage races are concerned with how to turn humans into sheep, gnomish mages want to know how humans can turn into sheep in the first place.
As a side effect of wielding arcane energy, the feelings of power obtained from being able to harness the arcane can result in the thirst for more power. As wowroleplay put it bluntly, a mage "is not unlike a drug user." As a result, mages are seen by other classes as formidable foes or intimidating allies. Others often fear mages for their potential to simply go insane from their lust for arcane energy. For gnomes, however, due to their fascination with the arcane, they are less feared than other mages, due to their lust for knowledge rather than power.
As a mage in a party of other adventurers, gnomish mages are called upon for their power, but are expected to keep a close eye on the battle, making sure that they do not draw attention from the enemy. However, the gnomish mage will often let the curiosity get to the best of them, and will often stray from the group to study their surroundings, or to examine specimens nearby, especially if its technological in nature. As a raid leader, good luck trying to get (let alone maintain) a gnome's attention if you happen to be in Tempest Keep!
Gnomish frost mages in particular are talented in the arts of water and ice manipulation specifically because of their knowledge of the scientific properties of water as well as kinetic theory of particle movement. Having metric precision, as well as knowledge of those properties allows a skilled gnomish mage to accurately harness arcane energy to create the perfect temperature fluctuation to cause nearby water vapor molecules to form the desired manifestation of ice. The theory is intense, but the gnomes know all the ins and outs of it, which makes them extremely dangerous assets to the alliance. If you're roleplaying a gnome frost mage, it would do you some wonderful good to look back to your high school science notes or even wikipedia.
As a science major as well as a true neutral alignment personality according to Wizards of the Coast's D&D personality test, I can begin to see why I was drawn to the race when I first began playing the game. As a result of what I have learned in my lore and RP studies, I have made special consideration to the backstory of not only Wimzig, but even the normal server characters that I have already made, particularly Bashertin, Miyo, and Lopen. Hopefully, once I make the appropriate retcons to wimzig's character, I can make character posts for him, as well as the other gnomes, and link to them from the sidebar of my blog. Until then, ciao for now!
16 minutes ago