Brother Against Brother

Brother Against Brother is the Major Easter Egg and main quest of M.A.R.S.. It revolves around the Mercenaries pulling one final favor for Dr. Van Lucker by constructing the Death Ray that will wipe out all traces of humanity on Earth while also helping out their leader, Cortex, by sabotaging Van Lucker's plans and using the Soul Stone to resurrect "The Angel". During the events, several twists and turns occur, including the reveal of the true antagonist of the Soul of the Machine saga and the final resolution.

You Will Need...
And, of course, skill and lots of backtracking and memorizing.
 * The Conqueror's Blade
 * Ray Gun
 * Soul Hacker
 * Plasma Gun v2.0
 * Electro Nades
 * Storm PSR
 * 4 Players

Step 1
"If you want to be free from this madness, pull for me one...last...favor..."

- Dr. Van Lucker, upon beginning the Easter Egg. Upon turning on the power, head back to the Research Station and press the use key on a loudspeaker. Dr. Van Lucker will begin talking and informing the players that he will only end the cyborg apocalypse if they help him construct the "Death Ray". Players will then need to start finding pieces of the ray scattered throughout the map. Most of these pieces can be found inside crates in the underground area while some parts are around the Research Station and surface areas. Add them to the tower found in the middle of the surface area. Once all parts are found, head back to the loud speaker to activate the next step.

Step 2
Press use on the loud speaker again. Van Lucker will speak again, only to be cut off by Cortex, who will inform the players to not trust Van Lucker but continue following his orders as it's "part of the plan". He then commands the players to capture 100 cyborg souls with the Soul Hacker and blast it into the antenna of a satellite dish outside. When accomplished, the antenna will charge for about a minute and a countdown from 60 seconds will begin. After a minute, the antenna will fire a laser and a player must throw an Electro Nade towards the blast's direction. It will ricochet and bounce off of walls in the Research Room before heading towards the tomb found in the underground area.

Step 3
Cortex will comment that they still need the Soul Stone and the Power Core in order to power the tomb. Before he can explain, Dr, Van Lucker will cut back in, demanding that the players begin setting the teleporter in the Research Station so that the Power Core can be delivered to the Martian Aerospace Research Station. In order to power it, players must throw 12 Electro Nades inside the teleporter. When completed, a glass door will cover the teleporter and an Ancient Egyptian-looking golden pedestal with the Power Core sitting on top of it will be seen.

Step 4
Dr. Van Lucker will then order the players to open the teleporter. However, Cortex cuts back in and begins to talk to Van Lucker, referring to him as "brother". The two will argue and Van Lucker will then spawn double the wave of cyborgs than normal, as he has figured out the Mercs' plans of sabotage and hopes that it will "change their minds and pick the right side". After all of the cyborgs are killed, he will begin to spawn more until Cortex announces that he managed to hack into the security system. Players will then have to dodge and take cover as each of the following events occur: When all of this is over, the glass door on the teleporter will open and players must obtain the Power Core.
 * Wall mounted Sentry Guns begin to fire at each corner of the rooms
 * Laser spikes pop out of the surface area at random spots
 * RPGs firing throughout each area
 * The entire underground are being temporary engulfed in flames
 * Water sprinklers going off in the Research Station, making the floor slippery for awhile and downing anyone who runs across
 * Earthquake shaking the entire map, causing damage to players the higher the elevation they are at
 * Players being teleported to random areas across the map

Step 5
Head back to the "Death Ray" and put the Power Core inside the middle compartment of it. Collect another 100 souls with the Soul Hacker and shoot it into the Power Core. Then, use the Plasma Gun v2.0 and fire all of it's ammo onto the rod without missing. Shoot one shot from a Storm PSR sniper rifle onto the very tip of the ray. Cortex will then advise the player to aim the ray towards the ground while Dr. Van Lucker protests against Cortex. The ray will fire and create a medium sized tunnel heading towards the tomb underground.

Step 6
Van Lucker will then yell at the players by telling them that they "did it wrong" and that there's one part missing, the Soul Stone, for which Van Lucker himself is in possession of. He will then advise the players to reactivate the teleporter, but with stronger power. In order to do this, fire 200 more shots with the Soul Hacker unto the the satellite dish' antenna and fire another shot into the tip of the ray with the Storm PSR. When both are charged, make sure that both are pointed towards an antenna on the roof of the Research Station by using the control panel. They will both fire blasts and power up the antenna. With this accomplished, a shadowy figure will be seen from inside the teleporter.

It is highly recommended that players obtain all perks before continuing onto the next step.

Step 7
This step is short and simple. It requires the player playing as Lv Bu to access a computer terminal in the computer room part of the Research Station. The other players will have to protect him as he completes a series of the following puzzles: When all of these are completed, the teleporter door will open and a cutscene will begin to play.
 * A maze like puzzle where you must get from Point A to Point B
 * A puzzle requiring to match letters with their number of place on the English alphabet
 * A shape puzzle where you order six shapes from least amount to most amount of sides
 * A small Sudoku-like puzzle

Step 8
Dr. Van Lucker is seen with the Soul Stone. He freezes the players and gives them a gloating speech as he begins walking towards the "Death Ray". He pulls the Power Core out of the ray and heads down towards the tomb bringing the characters with him. He unfreezes them as he places the Power Core and Soul Stone on top of the tomb. He begins to cite an unintelligible chant which gets interrupted by Trigger who pushes Van Lucker down to ground and kicks him in the head. A player with The Conqueror's Blade will then have to go up to Van Lucker and attempt to kill him with the sword. He tries to fight back by grabbing the blade and stealing it from him or her. You must quickly begin firing at him or he will plunge the sword down onto the ground resulting in an instant death and game over. He will fall back and the player who had The Conqueror's Blade previously must obtain it back and stab the Soul Stone and Power Core with it.

Step 9 - BOSS FIGHT AND FINAL STEP
Another cutscene will play and the players, along with Dr. Van Lucker and the tomb will be teleported to a darkened battle arena of sorts. The tomb will open up and explode a bright light as a pale woman dressed in red called "The Angel" is seen hovering above Dr. Van Lucker in the middle of the arena. She expresses disappointment in his abilities and for kidnapping the Martian people from their home and converting them into his own army of darkness and evil. She then fires a beam of dark energy at him and evaporates him to death (ala the "attack" scene from The Day After). She then focuses her attention towards the Mercs and plans on killing them to make sure "the other one" doesn't fall through with his plans.

The fight with The Angel is similar to the fight with The Hybrid from the Call of Duty: Eclipse Warfare Zombies map, "Unquestionable Ethics", but with several key differences. The area is a large, circular battle arena with a lot of room to run and gun around in. There are no cyborgs or special cyborgs that spawn nor appear during the duration of the battle. During the fight, the song "Stigmata" by Ministry will play. The Angel also has the ability to: When enough damage has been inflicted upon her, the screen will shake and flash. The arena will then blow up around her and the screen will cut to white before fading out into the final cutscene.
 * Fire beams of dark energy
 * Teleport the players into a platform-like area where they must dodge rocket-like projectitles
 * Lightning strikes from the sky at random positions
 * Melee attacks players, which will down them from one hit if close
 * Freeze players in place for 15 seconds at a time
 * Lighting a trail of fire towards players
 * Throwing spheres that will explode into a "flashbang" effect (temporary blinding and deafening players)

Final Cutscene
After defeating "The Angel", the four Mercs find themselves back on the surface of Mars along with the remnants of the tomb. They find the Soul Stone and attempt to grab it, but Dr. Wilhelm appears and takes the stone instead. He walks over to the Death Ray and reveals himself as the true mastermind behind the CODOL Institute's takeover of Mars and the Cyborg Apocalypse on Earth, using his ties with Dr. Van Lucker and feeding him his motivation to get back at his brother for what he did to him many years ago and humanity for becoming corrupted. He then inserts the Soul Stone into the Death Ray and charges it up. Cortex then speaks from the loud speakers and reveals he is inside the abandoned International Space Station orbiting Earth. He reveals that the Death Ray was intended to destroy Earth, but because he is immortal and possess mystical powers, the Ray will end up destroying him instead as it's powerful enough to even "end the curse of immortality". The ray is fired and destroys Cortex, causing a giant, reality merging portal to open in between Mars and Earth. The scene ends with Sergeant declaring that "it's not over yet" and the screen cuts to the stats and end credits.

Trivia

 * The Easter Egg contains elements from previous Easter Egg quests in the Soul of the Machine saga, as well as the "Escape Plan" Easter Egg from Unquestionable Ethics and the "Dark Portal" Easter Egg from L.U.N.A.R.