RoboTech: The Masters Saga: Southern Cross, Metal Fire, the Final Nightmare- 3 Vols in 1 Book

ROBOTECH v Second Generation DEL REY BOOKS CLASSIC VALUE THREE NOVELS FOR THE PRICE OF ONE
#7 SOUTHERN CROSS The Robotech Masters had come to Earth to finish the conquest their Zentraedi warrior-slaves had begun...and a battle-ravaged planet had to defend itself once more. That was when Dana Sterling, half-Human, half-Zentraedi commander of an elite Hovertank unit, stepped into the spotlight of interstellar history!
#8 METAL FIRE An alien fortress had crashlanded on Earth—brought down in the struggle between the Robotech Masters and Earth's Human inhabitants. Now the fortress dared someone to penetrate its dark mysteries. And who better to brave that ship than Dana Sterling's 15th Squadron ATACs—after all, they had brought the thing down to begin with!
#9 THE FINAL NIGHTMARE The Robotech Masters' Protoculture Matrix was degenerating, transforming into the Flower of Life—which was sure to draw the savage, merciless Invid across the galaxy to Earth. But the Army of the Southern Cross vowed to fight to the bitter end. And Dana Sterling raged a desperate war of her own to decipher her strange visions and the secret of her alien heritage...