.The forces of Black Unicorn Amber attacked various Amberites and Amberite related places on multiple occasions, never doing particularly well. Their last hurrah was the third battle (these things always seem to come in threes), in which a gigantic war train construct carrying the entirety of Black Unicorn Amber within it attacked the Shalomar Naval Base and made off with Merehallow and Kozue.
The final battle saw the war train lured into Lian's Shadow planet, Mechanus, and decisively destroyed by a large force of Amberites and their allies, assisted unexpectedly by the enigmatic, scone-baking, spatula-wielding Kuonji Inji. Woman and weapon were also retrieved. The unfortunate loss of the Talathian Pre-Logrus Power Sculpture of Pindin, used (in Kuonji's inimitable words) as a gigantic "Logrus nuke" against the war train, was deeply regrettable, as was the near total destruction of Mechanus in the process of the train's destruction. All hail torpedoes!
The Flawed Patterns in the train drifted back to the place that Black Unicorn Amber had occupied in Shadow. It is unclear what has become of the place since then, other than that Fuyutsuki has taken a hand in it. Rumors range from him using it as a giant Pattern reactor to him making it into the universe's most impressive model train table.
The family of the Black Unicorn is now thought to be nearly extinct. Of the original members, only Dworkin, Osric, and Finndo remain alive, all in Amber custody and likely to stay there.
There is one free Black Unicorner, although this fact is not widely known. This is Chloe of Rebma, daughter of Horatio and Kozue, concieved at some point during the extended series of events comprising the third battle.
It is unclear what became of the actual Black Unicorn itself, or even if there is such a being.