Halo series. Kilo-Five trilogy

"HALO: GLASSLANDS saw a very different development in the war that Earth has been fighting for so very long. With terrible losses on both sides, finally open hostilities have ended. But though a fragile peace has been established between Earth and the peoples of the Covenant, forces on both sides make that peace precarious. A schism among the Sangheili is gaining strength, with a splinter group trying to unseat the leader who agreed to peace; and...