Ninefox Gambit

In Ninefox Gambit, a brilliant but disgraced captain, Kel Cheris, must ally with an undead tactical genius, and notorious traitor, to recapture a star fortress lost to heretical forces. As they wage war within a universe ruled by rigid calendars and reality-warping mathematics, Cheris must decide whether she can trust the mind that could save her world...or destroy it.