My mission is to try and bring back as many characters as I can where the storyline would not be royally f'd up. Here's Scorpion, Frost (don't kill me for that, I actually would have liked her if she developed more), Ermac, Raiden, Karnak (new guy), Sareena, Smoke & Mileena. I'll post the story soon.

Scorpion
I was chosen by the Elder Gods to defeat the menace of the Dragon King. I had to shove all other vendettas aside to stop the new threat to all realms. But, my task was incomplete. On my way to defeat the Dragon King, Shujinko stopped me. The old fool fought and defeated me, using moves I knew from my greatest rival, Sub-Zero. If that fool had not stopped me, Onaga would be as good as dead as I speak.
Thus, Onaga is still alive, threatening the citizens of Outworld, as he did many centuries ago. I relinquished my pilgrimage for the Elder Gods, knowing that my ultimate task could not be complete until Sub-Zero was out of the way. His presence disgusted me, and stood for everything I found cursed. My only objective: destroy Sub-Zero.

Frost
In my greed, I had sealed my own fate by stealing Sifu Sub-Zero’s medallion. My world was inverted on it’s axis. My powers were backfiring upon me, and I was consumed by my own freezing ability. After bringing me to an ancient Lin Kuei temple, I was remarkably awoken by a mysterious ancient magic. When I awoke, my mentor was nowhere to be found. I did realize, however, that Sub-Zero had passed on.
Smoke, apparently an old acquaintance of Sub-Zero, had taken responsibility of the Lin Kuei when Noob Saibot and the Dragon King killed my teacher in a massive onslaught. Saddened and feeling guilty that my greed could have caused by master’s untimely death, I asked Sifu Smoke to train me in his maneuvers, in hope to defeat Noob Saibot and avenge my fallen master.

Ermac
The menace otherwise known as Onaga is sadly still in a great state of power in Outworld, and is quickly trying to throw a takeover of Edenia, just as our former ruler, Shao Kahn, did so many years ago. However, we still played our part in helping heroes of the greater good. The Champion of Mortal Kombat, Liu Kang, was wandering through the realms, as a lost soul. We understood his plight, being lost souls ourselves, and decided to help. In our journeys, we encountered five Earthrealm Warriors, under Onaga’s control.
After a long fight, Liu Kang’s body entered the melee, and began to run rampant. Liu Kang began to fight with his body, and we tried to rebound Liu Kang into his body. But, we could not. Instead, we were able to release the five warriors from their control, by occupying their minds, until the evil energy was released. After a short-lived victory, the Edenian Princess Kitana told us of the Dragon King’s plans. We must stop Onaga.

Raiden
In an act of foolhardiness, Shujinko let himself be deceived by the Dragon King, for the pure sake of adventure. I could not let him escape without punishment. Thus, after he fought Onaga, he lost. Others would believe that losing a fight was dishonorable enough, but I refused to think the same logic. I killed Shujinko for his misdemeanors. No one will put Earthrealm in danger ever again.
I have perpetuated my status as Elder God, but not an Elder God for the greater good. My only reason for existence is to keep Earthrealm in my iron fisted leadership. The looming threats of Shao Kahn and the Dragon King are of no concern to me. No one can stop me now that I am the first ever dictator of Earthrealm. The Elder Gods cannot even stop me!

Karnak
I was misunderstood as a person. Many shunned me from society, probably due to my special abilities. I figured no one would be able to grasp my plight, but I was wrong. In my travels, I met a sightless swordsman, Kenshi, and a knowledgeable shaman, Nightwolf. They understood me, and had abilities non dissimilar from my own. Thus, I joined them.
One day, Kenshi proposed that we comprise a clan of telekinetic warriors, much like himself and myself. At first, we had few recruits, but a mysterious warrior named Ermac visited us for a few days, to train us. After he left, the warriors and myself were ready to take on any foe. Kenshi mentioned one day that he was after a powerful sorcerer, named Shang Tsung, whom I thought was killed by the Dragon King. Whatever the reason, I followed my two mentors to Outworld: where Shang Tsung was last seen.
Sareena
I am a demoness, formerly doing the bidding of the sorcerer, Quan Chi, along with my sisters, Kia & Jataaka. However, a kind Lin Kuei protected me from the sorcerer’s treachery as best he could, but to no avail. Quan Chi killed me. After re-appearing in the Netherrealm, Kia & Jataaka tried to trick me into killing the Lin Kuei that killed them. I refused, and they nearly killed me when the demoness, Ashrah stepped in. Kia & Jataaka fled, when they spotted the white-clad demoness’ Kriss Knife, known for it’s automatic ability to slay demons.
I figured she simply chased them away just to kill me, but I was surprisingly mistaken. She requested my help in killing the spectre, Noob Saibot. I postponed her offer for a few years, to see what I could do until then. I emerged into Earthrealm, in the icy north, near the Lin Kuei headquarters, lead by the brother of the Lin Kuei that saved me. He offered me shelter, and I accepted. Once I was fully rested, I re-emerged in Netherrealm, conveniently near a battle between Ashrah & Noob Saibot. After the battle, I made a pact with Ashrah to defeat Noob Saibot.

Smoke
I am a cyborg, allegedly totally devoid of human emotions. However, I was not borne in such a way. I used to be a Lin Kuei, but was subject to an unethical project that made me the way I am. I was supposed to serve Shao Kahn, but was locked away in his dungeon, left to rust away. A few years later, a dark ninja came to unhinge me from my shackles, only to re-shackle me to do his bidding.
However, all was not right under the rule of Onaga. Whilst Noob was taking care of the Black Dragon assaulting Onaga’s temple, my old friend, Sub-Zero, was killed by the Dragon King. The reason he was so weak, was because Noob, Sub-Zero’s older brother, left him within an inch of his life in the Netherealm. I found Sub-Zero, nearly dead in Onaga’s temple. He asked me one request in his dying breath: become the Grandmaster of the Lin Kuei. I could not refuse. I left the next morning, Noob Saibot unaware.
Mileena
I am the clone of my greatest rival and “sister,” Kitana, Princess of Edenia. After she was killed by Onaga, I pleaded the Dragon King to keep her dead. But, my Lord had an idea. He had me parade around as Kitana, and control the extensive Edenian army, led by Master Bo’ Ra Cho & his apprentice, Li Mei. Everything was coming into fruition. Baraka took care of the master and his apprentice, as well as the Black Dragon. However, things were amiss.
The warrior of souls, Ermac, freed the soul of Kitana from Onaga’s control. It is only a matter of time before Jade & Kitana come for me. But, unbeknownst to them, Onaga and I have a huge surprise for them. I tipped off my Lord about a King, that Shao Kahn had killed so many years ago. If Onaga revived that king, we would leave Kitana & Jade in their tracks...