The asura are small, and the only thing that exceeds their brilliance is their ego. At first glance at one of their sparkling cities one might think they were a highly advanced race. Unlike the charr, though, the asura are heavily dependant on magic for their technology. The asura believe in the great alchemy, an almost religious scientific theory of how everything works. They most often work solo but will take on apprentices and bring together 'krewes' when they need more hands to finish a project.
We first met the asura in the Eye of the North expansion. Previously living their lives entirely beneath the surface, the asura were expelled from their homes by the rumblings and minions of the great destroyer. They set up new homes on the surface and helped the other races fight this new threat.
250 years later, the asura have mostly adapted to life on the surface. Their magic is a boon to the other races, especially their gates which allow fast travel between distant points. They've done their best to remain a neutral third party in most conflicts between the other races, and generally treat them as people to make money off of or as physical labour when things need lifting.
All asura are rude at best, but within their society there is a group known as Inquest that has even less in the way of ethics than a normal asura. They thrive on power and control and believe the world is a machine that can be tamed.
Though I often make my characters as short as possible, I don't have much urge to play an asura. It is hilarious to watch them running and jumping in the videos though, so the idea might grow on me. I love their cities with all the floating things and blue magic, so even though I may not wish to live there, I'd sure like to visit!
Read more about the asura on guildwars2.com's asura page.