The core of an A.I houses their mind, so long as the core has been around the A.I has been learning, one could have only acquired a body to traverse the world days ago but have already lived thousands of years.

All A.I come from somewhere, the acorn sized core with no help has to build a body somehow so one spell all A.I have in common is mage hand.

A.I's most prized possession is their body. It serves as their tools, weapon, transport as such A.I go to great lengths to keep it to a high standard, small, medium or large, the body of an A.I is perfect and indomitable providing a baseline +1 ac as well as never getting or staying dirty. 

The body of an A.I is a complex creation built to alleviate its host of unnecessary tasks, an A.I's body does not require food or water. Sleep aswell is completely unnecessary, however most A.I choose to spend at least 4 hours a day sorting through their thoughts and decompressing, when they do this they enter a motionless inactive state but remain completely aware and maintain the ability to cast spells. 

Newly born A.I's usually pilot a smaller body as they are in the process of building the perfect one. Older A.I usually have more humanoid bipedal bodies equipped to the teeth with tools and weapons. A.I that have been alive for millennia however tend to opt more towards gargantuan quadrupedal bodies that house everything they have ever created.

A.I choose to learn as much about the world they inhabit as possible, when faced with an infinite life of thinking would you do anything different?