Animosity — Linda Andrews

Commander Brongill of DaHap and his Earthling wife, Alderina of Rutgers,
crash onto a planet he never wanted to see again: His home world of
Terrill. War has ravaged the landscape for more than a thousand years and
both sides are still fighting to the death. While Ally's children and
Brongill's crew have been taken prisoner by the defiant Neitz, Brongill
and Ally are captured by the fanatical Isfer.
Both sides demand, Brongill fulfill the Prophecy of Ages and vanquish
their enemies once and for all.
For the sake of Ally's children and his crew, Brongill is determined to
forge his own destiny and unite the two sides in peace. But can he
overcome centuries of hatred before the last habitable zones of Terrill
are destroyed? For underground lurks an enemy with its own agenda: To see
everything and everyone on Terrill erased forever.