Kate is grumpy about not being able to save Threshold, and talks to Kurt, who asks if she's tried everything. Kate gets an idea.
Kate goes to Genosha and reveals the plan: a circuit to send the spirits of everyone who died in Krakoa to the past in the box-thing, which then becomes the first generation of what eventually becomes Threshold. This is why the next step of human evolution exists billions of years before any type of humans exists. The circuit is Polaris, to handle the Mysterium, Tempo, for the time Travel bit, Cerebra for the DNA and tech side (who is late), Theia to get everyone to fit in the box, Fang to regenerate everyone in the past, and Wicked to get all of Genoshas dead (human and mutant, including Kate's dad) on board. The humans are haunting Genosha and the mutants are communicating via the Waiting Room.
Kate didn't get any sort of permission from the Council to do this, which I hope will make for a fun issue of Immortal down the line
Fang goes after Brimstone Love and his cult, it doesn't matter and is completely unrelated to the important part right now.
TLDR: Threshold is a future version of Genosha sent back in time, which means technically Kate created Okkara and therefore Krakoa.