Starting with A, I couldn’t think of anything more meaningful to the Skylanders Universe then talking about the Arkeyans. The Arkeyans play a big role in the first two Skylanders games: Skylanders Spyro’s Adventure and Skylanders: Giants. The Arkeyans can be found all throughout the Skylanders Universe.
The Arkeyans exist to protect Skylands from The Darkness. Their origin story has actually been lost in the mists of time (no one knows where they came from.) With their knowledge and power over the elements, they began to experiment with magic and technology to create new machinery. The Arkeyans were the first to discover the Tech Element and then merge it with the Magic Element. This led to an explosion of technological advancement.
Two different rival factions appeared from the Arkeyans. There was a peace loving faction and a war driven faction. Eventually the peace loving faction disappeared, leaving only a high population of war driven Arkeyans. The Empire spread.
The original Giants of the Skylanders Universe banned together to free Skylands from the Arkeyans. They wage battle with the Arkeyan king and removed the Iron Fist from his defeated hand, destroying the king and deactivating the robots. However, that act swept them from Skylands and dropped them on Earth, where they were buried for 10,000 years.
It wasn’t until Kaos was defeated by the New Portal Master (player), that he reactivated an old Arkeyan war machine, allowing for the Giants to become unearthed and return to Skylands to start the battle anew.