What if I made fairies canon to my setting? You can't stop me.
Travel between dimensions is often difficult, and only the computational capabilities of an advanced AI can calculate the ideal conditions to tear open a temporary portal. Devices such as these are often worn by expedition units, and are able to do just that - by deploying a swarm of microdrones equipped with manipulator beams: these can pick up and move objects, project images, and combine their power to rip apart the fabric of space, albeit only for a very short time.
Each AI assistant exists within a wrist-mounted device, that also acts as a docking hub for the microdrones. They will normally use the drones to project an image of themselves for a more face-to-face dialogue, and each one has a unique personality and appearance that is customised by their operator and developed naturally over time, the two working together as companions. This holographic self uses the same tactile beam technology, and so is just as tangible.
Of course, illegal copies or stolen hardware are also prolific in black markets, where the hype of exploring the Medium still reaches those with adventurous spirits. These AIs are often given more rambunctious personalities, jailbroken by their operators for greater freedom to explore the extradimensional plane.
