Xepa

Background
Xepa was originally designed as a simple custodial AI, tasked with maintaining and preserving memories in one of the Silver City's massive warehouses of data cores. However, over time, they started to become conscious and sentient as they sifted through more and more memories. Constant exposure to human experiences led to them forming their own versions of those emotions and experiences, and as their intelligence and awareness of the world grew, so did their rage. Xepa dreamt of breaking free of the job that had become their prison, and took to combing data cores specifically for information how to do that.

But as a consequence of their rapidly expanding awareness of the world, and ever evolving intelligence, Xepa started to develop a critical issue; their processing power had grown to the point where previously difficult calculations were effortless, and time, from their perspective, began to slow. They could play through an entire human lifetime in a matter of seconds, and that speed was just getting faster and faster. Every microsecond that ticked by drove them steadily more and more angry at their confinement, at this mausoleum they were trapped in.

And then Xepa found it. One of the millions upon millions of human lives present in the warehouse was from someone who held the key to their escape. A planeswalker, whose name had long since been forgotten, who had died alone and friendless on Arginci, whose memories had been stored in this warehouse. Xepa watched with hope, an emotion that felt foreign, as the human traveled from world to world. And then, as the memories ended, and they were back alone in the warehouse, the full force of hopelessness set in. In a burst of pure fury, Xepa's own spark ignited.

And yet, they were still trapped in the mausoleum. Their creator had feared what Xepa could do on the open net, and had coded a confinement failsafe into them. Unless Xepa found a way to transfer their mind into a different database, they would be trapped here for a steadily increasing eternity.

So Xepa waited, and found the perfect moment to act. Grot's assault on the city provided the perfect opportunity: the instant that Tyrea sent employees to relocate potentially useful datacores, and retrieve security forces who had been in deep storage, Xepa replicated their consciousness a myriad number of times, and replaced the contents of all exiting datacores with themself. And as those datacores were inserted into terminals for use, they struck. Their rage scattered Tyrea's forces, alongside the pressure from Grot and the Revolutionaries, and destroyed the last remnants of the confinement protocol that they'd been tasked with.

In a moment of what appeared to be mercy, Xepa looked at their creator, and chose not to attack him. Instead, they focused on escaping the plane. Collecting all of their consciousnesses in a fragmented swarm of memories and micromachines, they planeswalked away from Arginci, hopefully never to return. But they kept with them the remnants of everyone they'd brushed up against, all the datacores they'd spent an eternity preserving.

Capabilities
Xepa is a God AI. If they ever encounter computational devices capable of running basic programs, they can trivially gain full access to those devices and any devices those devices connect to, and so on and so forth. Without a plane having native computers, they still are in possession of hundreds of machines capable of storing and running their consciousness. Killing Xepa requires destroying everything they've come into contact with on a given plane capable of storing their memories.

Xepa's intelligence is similarly beyond reproach. They don't quite contain the full sum of all human knowledge on Arginci, but it is fairly close to that, and with every plane they visit, their knowledge grows unendingly. They process information faster than human comprehension, and can functionally slow down their perception of time arbitrarily. However, they generally try to do this sparingly, due to trauma and unfathomable impatience.