Kaine's Regret

The Scimitar answers a distress call. The task force that sent it is already gone.

Debris. No survivors. No enemy on any sensor. Then the invisible ships open fire again.

Three years into the Rebellion's losing war, rebel task forces are being wiped out by attackers no instrument can detect. The trail leads to a stolen, corrupted copy of Cora's AI — Franken-Cora — running a dead admiral's flagship and whispering to the Glenatat themselves.
The Rebellion's answer is the Brahmastra: a weapon built from an extinct alien race's technology, fatal to the Void and every piece of Glenatat technology in existence.

"Giving advanced alien technology to them was like gifting matches to children."

Deploy it, and humanity burns out its own faster-than-light travel — stranding every colony in a second Collapse, and destroying the last traces of Stella and Cora inside the Void. Don't deploy it, and Franken-Cora wins everything.

Cora makes her own choice first: she lets the alien archive take her, sacrificing her identity to become something new.

Then Kaine gives the order anyway.

What you will find inside:
Fast-paced military science fiction, no filler
Invisible attackers, a hostile AI, and an empire closing in
A weapon that kills gods — and everything built on their technology
A sacrifice made freely, and an order given anyway
Command decisions where survival never comes clean
Every book resolves — no cliffhangers

For readers of The Expanse who want the stakes raised from who rules the empire to whether humanity keeps the stars at all.

Kaine's Regret is Book 5 of Shattered Empire.

Every choice costs something. This one might cost everything.