1. Johnny is descended from a race of mystical warriors and has learned how to tap into his powers. Liu has learned how harness his Ki
2. He killed the Great Kung Lao, helped Shao conquer Kotal's people and was unbeaten in Mortal Kombat for 450 years. He's a pretty big deal but people are mistaken in thinking he killed Cage in any canon or that Cage killed him. It's a franchise in-joke that Johnny dies in every game but he survived from MK1-MK2. If he died in MK1, he'd have to be revived for MK2 and the first character to return from the dead in the original timeline was Mileena. She was killed by Kitana in MK2 and resurrected to serve Shao while actually serving Shinnok in UMK3.
The Cage-Goro rivalry is explicitly movie-related. So far as I know, the only shoutout to that in the games was the Cage-Goro MKA edition. Remember, MK1 was a tournament. Only one guy got a shot at Goro: if he lost, Goro won the tournament. If Cage was killed by Goro in MK1, Liu would never have had a chance to defeat Goro. So logically, the final match of the tournament was Liu killing Goro. Liu then challenged Shang Tsung because (if I remember correctly) the tournament was originally governed and held by the Shaolin order but Shang over time corrupted it and stole it away from the Shaolin as they got weaker and weaker after the death of the Great Kung Lao. Technically, even had Shang killed Liu, Earthrealm would have won the tournament. The idea that Shang has the right of a former champion to jump into the tournament at any time is another movie invention: it's never been clarified what actually happened in Shang's first tournament run. We do know his primary motive for winning the tournament was that the winner becomes immortal, which is Shang's thing. Some sources say he was spared by the GKL and made a deal with Shao for his soul in return for eternal life via soul stealing, others say he cheated in his first defence of his title and was cursed by the Elder Gods to live only by soul stealing. Realistically, Shang could never have been the champion of Outworld anyway: if Bo couldn't fight for Earthrealm because he was born in Outworld, Shang couldn't fight for Outworld because he was born in China. He was the Grandmaster, the overseer on behalf of Shao. When he subsequently fought for Outworld, in MK2/3/DA, they weren't real Mortal Kombats, sanctioned by the Elder Gods. They were, respectively, a tournament invented by Shao as an excuse to kill Liu Kang, a war and a tournament invented by Shang and Quan to steal souls for their zombie army.
So yeah, the whole Goro-Cage thing is an invention of the movie. The climactic battle of MK1 was Goro-Liu and then Liu decided to clean house and kick Shang's ass.
In original MK1 canon, Goro lost to Liu and was spared because Liu at the time was a hardcore pacifist. He then pissed off into hiding until MK4 when Shao Kahn was weakened and Kitana offered an alliance in separating Edenia and Kuatan from the rest of Outworld. Goro was actually a good guy in MK4 until Noob assassinated him. Shao resurrected him in MKD and he went back to being head of the goon squad.
Cage survived MK1 and, according to an audio file leaked in the run-up to MK3, was killed by Kintaro in MK2. However, this would violate the idea of MK2 still being a tournament: if Cage couldn't fight Goro, then how could he fight Kintaro as the canon has Liu beating both? The only way it would work is if Kintaro was a basic level entrant in the tournament for Outworld like Baraka which we know isn't the case: I theorize he was Kahn's nominated champion but Kahn reserved the right to face the victor. Remember that MK2 was NOT a Mortal Kombat tournament under the rules of the Elder Gods: it was cobbled together by Shang and Shao as a Plan B in case Goro lost because Shao refused to wait another 500 years.
The accepted canon now seems to be that Cage was killed by Motaro in the beginning of the invasion: this is stated in MKDA and seems to be confirmed by the fact that he survives in MK9 after Raiden tackles Motaro through a bridge. He wasn't in Trilogy and came back in MK4 because he saw his friends fighting Shinnok while he was in Heaven and asked the Elder Gods to restore him to life so he could help them. He then died at the hands of Shang and Quan, resurrected as a mindless zombie by Onaga and was killed at Armageddon. Then we reset and MK9 story mode.
3. Right now, the Elder Gods. Their allegiance is to an ordered existence where the realms obey the rules of MK. Their capabilities are uncertain but they easily obliterated Shao in MK9. Overall, the most powerful individual being was the One Being. In the beginning, he was all of existence until the Elder Gods forged the Kamidogu and used them to kill the One Being. His existence was shattered into the realms, the primary ones being Earth, Netherrealm, Chaosrealm, Seido, Edenia and Outworld but there presumably are more we don't know about, minor ones are absorbed into Outworld all the time. The One Being now acts by influencing the actions of individuals who could merge realms: were all the Kamidogu to be reunited along with Shinnok's amulet, the wielder would gain unparalleled power and thus be able to merge the realms, thereby restoring the One Being to existence. This is the plot of Deception: Onaga is deceived into acting for the One Being in a similar fashion to Shujinko acting for Onaga. Shao has also been speculated to be acting under the One being's influence: he doesn't pick sides, he just wants the realms re-merged so he can exist again.
4. Raiden's overall power levels are unknown but Shao was once the protector of Outworld as Raiden is the protector of Earthrealm, it can reasonably be assumed that he's at a similar level to Shao but significantly less due to Shao absorbing billions of souls. Millions of years ago it was Raiden who was charged with the Elder Gods with defeating and imprisoning Shinnok when he 'fell' from the Elder Gods. It destroyed whole realms and drove the Saurians from Earth to Outworld but as Raiden was victorious with the help of the Elder Gods, we can presume Raiden is extremely powerful in his godly form. His mortal form is less powerful but still capable of almost matching Soulnado Shang and Amulet Quan. And he can't die of course: he always reforms.
5. Originally in the movie but hinted at in MK4 and explicitly confirmed in MKDA. One of the best parts of both characters because it makes sense: Liu is the champion and thus immortal, so he has to watch his friends and loved ones die while remaining forever young. Kitana is 10000 years old and looks to be in her early twenties so they're a perfect match. He'd probably still pre-decease her as nobody could reasonably expect to win over 20000 MK tournaments on the bounce.
6. The Elder Gods do not directly interfere in the affairs of the realms. Thus Mortal Kombat and thus in Deception, when they knew they needed to act to destroy Onaga and prevent the One Being reforming, they transformed Scorpion into their champion.
Remember, from their viewpoint Shao has done nothing wrong. Okay he renounced his Godhood but it seems he's entitled to do that. Every realm can declare war on another and try to conquer it: it requires 10 straight victories in MK tournaments. This was implemented by the Elder Gods for the same reason City States in Ancient Greece didn't send forward armies of thousands, but instead a few hundred: why have massive destruction every generation when you can just have a few dozen or a few hundred? (This is what made Sparta so terrifying, it maintained a standing army of thousands of highly trained troops. Contrast that with the Theban Sacred Band) It minimizes the losses and the Elder Gods could be reasonably certain that most realms will throw up a great warrior once every half a millenium. And if not, well maybe they deserved to be conquered. It isn't until Shao violates the rules of MK that they intervene: in the original timeline, they don't intervene at all: Liu beats Shao on his own in MK3.
7. Bi Han killed Hanzo, Scorpion killed Bi Han. Kuai Liang was getting the better of Scorpion until he was kidnapped by Sektor and Cyrax. Cyber Sub was clearly OP in terms of story but it seems he's being quietly forgotten. Which is a good thing, because he beat Ermac but Ermac destroyed Jax but Cyber Sub beat Kintaro and Goro simultaneously but that would make him the greatest warrior of all time, since only Kung Lao and Liu were capable of beating either and that was one on one. But then Cyber Sub got pwned by Sindel but then Sindel was killed by Nightwolf. But Scorpion beat Nightwolf, but Sub Zero beat Scorpion. Measuring power levels through the story mode is pointless and extremely FUCKING frustrating.
Overall, it's pretty even between them. I'd say Scorpion beats Bi Han/Noob but Kuai Liang beats both (ignoring their enhanced forms with the Dragon Medallion for Kuai and as the Elder Gods Champion for Scorpion). Bear in mind though, Scorpion gets more and more powerful the longer he spends in the Netherrealm. So were he to fight Kuai in the Netherrealm, he'd likely win. Arguably that's the only reason he defeated Bi in the runback.
@Shad how'd I do? Might need Razor's corrections
