The Silver Civilization can be seen as Gods of Arcadia in some way shape or form. Both their technology and the magic they derive said technology from are incredibly powerful, far beyond what any of the other magic types are capable of. Silvites were more than capable of creating and prolonging life at will using the Silver Moon's power of void, and also created the most powerful Gigas in the world - so powerful that it could influence all six moons. When the Old World era ended with the Rains of Destruction, the remnants of the Silver Civilization was sent into outer space where for the next several thousand years they "judged the world" by their standards and eventually decided to bring down the Rains of Destruction again when they saw how Valua was behaving. As Valua's militaristic policies would lead to another world war, the Silvite Elders decided to purge the world again with the Rains before things got out of hand.
Over the years, the Silver Civilization has been greatly reduced in size; the remnants of their civilization are located on the lost continent of Soltis, under the Silver Moon. Thousands of years ago the Silvites created the Gigas Zelos out of nothingness, using its great power to call down the Rains of Destruction and cleanse the world. After the other Gigas have been sealed (save for the obvious exception of Plergoth/Rhaknam), the Silvites sealed Zelos with a shield that was designed to open only with all 6 Moon Crystals in tow. However, to make sure that no one ever found out about Zelos, the Silvites forcibly sank their continent Soltis below the clouds, creating The Vortex, left Shrine Isle sitting in the middle of nowhere, and sent their main shrine, The Great Silver Shrine, into outer space. Over the years, the Silvite population, most likely due to a lack of living space and their ability to create and extend life at will due to the power of the Silver Moon, was greatly reduced. By the time Vyse's story begins, the Silvite Civilization had a single digit population. By the end of the game, Fina is the only surviving Silvite in the entire world as the entire shrine was sent plummeting towards Soltis by the Elders in an effort to aid Vyse and crew to defeat Ramirez.
The technological prowess of the Silver Moon is incredible. The Silvites possessed the ability to create autonomous life in the form of the androids that guard their ruins. The Silvite Elders are also able to maintain themselves in stasis in order to lengthen their lives. The Silvites are also able to artificially create biological life as both Ramirez and Fina have a Silver Moon Crystal used as their "life force." Similarly, Cupil was an artificial life form created by the Silvites. Last but not least, the Silvites are also able to create advanced transporation technology, primarily teleportation and space travel. Valua's 5th Admiral De Loco seems to be aware of the high potential of Silver technology as he states that he has long vested great interest in the technology of the Silver Civilization, which (at that point in the game) implies that Silver technology is the only type of technology that surpasses the Yellow technology seen in Valua.