Guardis are not biological as far as we can tell. They consist of a rubber exterior with an aluminum skeleton. They don't have any source of power, so it's probably possessed. They serve and protect their creator with their life without question, and though they're not very dangerous individually, in large numbers, they can become unstoppable. There have been at least 5,000,000 of them counted to exist throughout the world, but there's definitely way more.