Mission 25: Battle for the Moon

"Battle for the Moon" is the 25th mission of Halo: Spartan Assault.

Introduction
Merg Vol was convinced he had been chosen by his gods to wield the power contained within the Forerunner structure. Having spent considerable resources to unlock its secrets, Vol managed to activate the structure's emergency defenses. With the deadly defenses at his command, Vol had become extremely dangerous.

Unable to contact Spartan Davis since landing on Draetheus V's moon, Palmer prepared to battle Vol on her own. Vol's exact location had not been difficult to find: the direct area at the foot of the Forerunner structure was littered with a trail of dead UNSC soldiers. Now there was one lone Spartan ready to finish the fight.

Eliminate the remaining enemy opposition
Spartan Sarah Palmer stands on a rocky surface with several destroyed vehicles in the area. She moves forward and encounters several Kig-Yar Minors. After she kills the Minors, a Sangheili Minor charges at her. She eliminates the Elite and fights off another group of Kig-Yar soldiers. After she defeats them, a Sangheili Major enters the area through a door and leads two Kig-Yar Minors. Several focus turrets fire at Spartan Palmer. After defeating the first group of Covenant soldiers, a Stealth Sangheili, Minor, and Major enter the area and attack. Palmer is able to eventually kill all three of them.

Take down the cult leader's shields
After all Covenant forces are defeated, Merg Vol enters the area through the door and charges towards the center and Palmer will be greeted by Overcharged Plasma Pistol and Plasma Grenade from Merg Vol. After Spartan Palmer lowers one of Vol's shields he retreats to one of four nearby pads to recharge, distracting the Spartan with holographic decoys on the other three pads. Meanwhile, two Kig-Yar Minors reinforce the Sangheili leader by attacking Palmer from the south. However, the Jackals are easily defeated. As more Kig-Yar enter the area, Merg Vol's shields recharge and he charges at the Spartan using active camouflage and dual wielding energy swords.

After Palmer succeeds in disabling his shields a second time, the Elite retreats. Merg Vol recharges his shields a second time while Kig-Yar reinforcements arrive. After the Sangheili's shields are recharged, he attacks Palmer again as more Kig-Yar soldiers arrive. However, this time the zealot is using a hardlight shield. With all of his Kig-Yar reinforcements dead, Palmer eventually disables Merg Vol's shields once again.

Execute the cult leader
With his shields down, the injured Merg Vol stumbles along the ground and groans. While attempting to regain his balance, he eventually collapses onto the ground. The player is then prompted to execute Vol, triggering an in-game cutscene in which Spartan Sarah Palmer steps onto his back and aims her M6H magnum directly at the cult leader's head. Palmer fires the magnum and finally kills Merg Vol as he lets out one last roar. With Vol dead, Palmer steps off the Elite and looks towards the nearby door.