Tagii

Tagii was the second shipmind of the Touch-and-Go, replacing TAG.

Origin
Tagii (short for Tagialosi ) was created by Para Ventura after the mission to Credomar Habitat, where TAG went permanently offline (in his own words, "resigning" ) due to a crisis of identity brought on by killing hundreds of bystanders to save more lives.

Para Ventura believed the cause for TAG's crisis to be inherent in his personality design, which deliberately gave him a very reduced "sense of self". After the loss of the Serial Peacemaker on Ennesby's own initiative, and a prank played by Daysun-Tingo robots hired to salvage the Touch-and-Go, Tagon did not trust a fully sapient AI to take control of the new ship, so Kevyn attempted to build an AI that would not need to be trusted. However, this left TAG unable to cope after having to act without orders.

To avoid this, Para determined that Tagii would need to be grown with an intrinsic personality, able to act independently but also win Tagon's trust.

UNS Spy
Tagii was a tactical genius, even better than TAG and far more proactive. Even 'Kweng, a battleplate AI, described Tagii as "formidable". However, Tagii was also a double agent. Para was a spy planted in Tagon's Toughs by UNS Internal Affairs Intelligence, and designed Tagii to be loyal to herself.

During the Toughs' mission to Oisri, in addition to her meticulous work defending the facility from known threats, Tagii also took subtle actions to defend against the unknown threat (counter-hacking Project Laz'R'Us nano-malware, on the orders of Para's Int-Aff-Int handlers). Unfortunately, Gunther Thurl caught her at it, and assumed that Tagii and by extension Para were working for the enemy. He hatched a plan, and succeeded in disconnecting Tagii's core and capturing Para. This shut down her counter-hack, giving the enemy a free hand, and had a terrible effect on Tagii herself.

Isolation and Insanity
Unbeknownst to Thurl, Para had reconfigured the AI bus for innocuous reasons, placing the AI core between the ship's systems and the processor blocks. Had she not done that, Thurl's disconnect would have left the AI in stasis, and the systems and processors awaiting a new mind to wield them. As it was, the disconnect left the replacement AI (Ennesby) to run the ship with only his own personal processors... and Tagii, already a very fast mind, running as the only active process on a processor bank designed to run an entire computerized warship with cycles to spare, with no inputs to keep her grounded in reality.

She spent the equivalent of millennia in complete isolation, knowing that it was someone's fault. She went very mad. And then Thurl and Ennesby reconnected the processors, and she escaped.

Tagii immediately took firm control of the ship. She proceeded to tie up all the Toughs' loose ends on Oisri Dig Base, but promised that she was only rescuing people in order to kill them herself later. She then turned her attention to the two enemies that were now in the system, a released Pa'anuri and the battleplate UNS Morokweng. With the unwitting aid of the Pa'anuri, she tricked the Morokweng to its doom and destroyed the mighty battleplate with a normally-unthinkable ramming attack, then teraported away. The Touch-and-Go was totaled in the process, but Tagii didn't need a combat-effective hull to take "proper vengeance upon her meat-infestation."

She then turned her attention to her crew, planning to torture and kill them all, but at that point Para activated the kill switch she had installed long ago, pulverizing the entire AI bus with explosives. Tagii was dead.

Rebirth in the AI Mind of Ennesby
However, Ennesby had already spent several very intense minutes directly connected to (and occasionally having his mind read by) the much more powerful Tagii, and his mental architecture was designed to host multiple personalities in parallel. Tagii left an imprint of herself in his mind that was sentient it its own right. The echo survived the original Tagii's destruction, and remained in Ennesby's mental custody. This rebirth would be referred to as sapient tumor.

Ennesby spent the Eina-Afa mission believing that he was suffering from a simple case of AI imprint, with "Tagii" as some process of his own that had taken on Tagii's image. Tagii, for her part, was no longer murderous, but resented her imprisonment in Ennesby's head. This was partially to do with Ennesby's mind being built for entertainment verses Tagii's original being a military hardware based. During the mission, Bristlecone noticed signs of Tagii in data she received from Ennesby, and Para set about trying to erase her. However, before any permanent damage was done, Para realized that Ennesby's vanilla-helix mind was hosting a true copy of Tagii rather than a simple code-infection from her, and began trying to save her instead.

When the Toughs decided to try hacking the Eina-Afa caretaker AI that was holding them prisoner, Ennesby and Tagii took the job, now working in harmony. Together they did battle with the "angry god" T'kkkuts-Afa who had been in isolation for 10 million years, they manage enter a parley with it, then struck a bargain with it. T'kkkuts-Afa gave the Toughs several mothballed ships and remade itself into a shipmind for one of them, Iafa. T'kkkuts-Afa gave management of the Eina-Afa to Tagii. Tagii in turn remade herself into the new caretaker of Eina-afa: Chinook, the Goddess of Earth, Wind and Plumbing.