Star Wars Knights of the Old Republic III: The Unknown Regions 2.0
It's two years after The Sith Lords. A high council of bureaucrats from Alderaan have been assassinated. You were one of the Jedi who switched off the lightsaber years ago, turned an private investigator, who has been sent to discover who the assassins were. The Alderaanians don't hire the Republic to investigate this, as they are trying to establish independence.
You arrive on the planet and start snooping around, to the point where the assassins begin taking notice of you. Eventually the assassins confront you to shut you up. Only the assassins are Sith and discover you are force sensitive, so they make you an offer - join them or die.
They killed the bureaucrats because they were pacifists and wanted to have them replaced by leaders who are more accepting of the Sith. These Sith, like the Sith of KotOR II, only care about the destruction of the Jedi. If they can, they will manipulate everyone possible into perceiving the Jedi as vermin, killing those who defy them. Anyway, a Jedi Knight tracking the events arrives on the scene.
Now you must make a choice - help the Jedi or help the Sith. Whoever you help, wins the fight. If you help the Sith, you go with them to some Sith planet (not Korriban) to train. If you help the Jedi, you go to Coruscant to train, or maybe Tython, where the Jedi first originated from.
During your training, you can set the gender and alignment of Revan and the Exile in a history test. Following your training, you're sent, under the guidance of a master, on an important mission, but regardless of who you help, the planets you visit during your adventure are the same. This master should be a history buff who can provide useful background information on the events of KotOR I & II to new players.
Anyway, if you helped the Jedi, then you must find the MacGuffins that lead Revan to the discovery of the Sith empire. If you helped the Sith, then you must find the MacGuffins and destroy them so that the Jedi can never discover their empire. Throughout your adventure, you will be confronted by Jedi or Sith trying to stop you from completing your mission.
I'd say the MacGuffins should be split amongst four or five planets. They don't have to be Sith planets, either, as the enemy Sith I had in mind are remnants of Naga Sadow's empire. They may have conquered a few planets from the Great Hyperspace War and "forgotten" about them for a time, until they begin attacking the Republic again.
During the process of discovering or destroying the MacGuffins, your master is killed in battle. Once you have discovered or destroyed all the MacGuffins, your allies gather and a space battle on the fringes of the outer rim ensues.
Just before that, I think would be a good time for the player to potentially have a confrontation with their party members. This would depend on influence and the alignments of the crew. Light side and dark side won't work together, so in that case, there would be a fight, as there was in KotOR.
If you are light side, then the Jedi, the Republic and the Mandalorians gather and go and confront the Sith. If you are dark side, then the Sith you helped are planning to overthrow the emperor, Lord Astaroth, and so go to do battle with them anyway.
As you would discover throughout the plot, civil wars are not so uncommon among the Sith. In fact, the Sith recently plunged into a civil war, caused by destabilisation of their leadership as a result of assassinations of key leaders.
Revan and the Exile were the ones responsible for the assassinations. Astaroth doesn't know that, though, and thinks one of the Sith Lords, Darth Ra, was responsible, because she took credit for them to get closer to him.
She fabricated evidence that that the dark council were planning to overthrow him, so he ended up being pleased about the assassinations. As a result, Ra became Astaroth's new apprentice.
Anyway, during the space battle, you board the enemies capital flagship and fight your way to the main bridge to confront Ra. You kill her and your allies win the space battle. During your adventure, you gather more allies prior to the battle, as you did in KotOR II. They could be from the Exchange, they could HK droids and so on, the types of allies would depend on alignment.
Following the space battle, you and your army march on further into the depths of the Sith empire, for the next battle, which is against forces orbiting above the Sith world of Khar Delba, who are already engaged in battle against each other. Your ship is shot down in the space battle and you crash land on the planet.
Since the planet is crawling with Sith, light side players must play along and pretend to follow the Sith. During the search for parts to repair the ship, you come across cult members who identify themselves as Revanites, who identify their leader as, you guessed it... Revan.
Revan plans to defeat the Sith from within. Revan infiltrated one of the Sith factions, rose through the ranks, became one of the leaders, assassinated the dark council members and instigated a civil war between them. The Exile followed suit and joined the war effort. They both look like this:
The Exile takes on the appearance of Darth Nihilus, as it turns out Nihilus was the Exile's other half, as Revan explains to the Exile when they meet again.
Anyway, you learn that Revan was interested in something at the Sith base of Naga Sadow on Khar Shian, the moon of Khar Delba. Revan went there to check it out, along with the Exile. Once you find the parts to repair your ship, you go to Khar Shian and fight your way to the base, which is heavily guarded.
Once you're inside the base, you won't find Revan and the Exile. What you will find is an ancient chamber with Sith holocrons. Revan believed that this chamber and the blade of the first Sith Lord Ajunta Pall, was significant, as you will soon discover. The holocrons try to corrupt you, light side players can turn to the dark side at this point if they choose.
In the base, you also find information about Revan's plans to attack the Sith capital, Kaas City, on Dromund Kaas. Once you leave the base you have a nice surprise waiting for you just outside the entrance - Revan and the Exile, with several Revanites standing behind them.
Revan explains that after Astaroth's forces were defeated above Khar Delba, Revan called off his or her attack fleet from yours. Revan, impressed by your ability to storm the base, explains the importance of stopping Astaroth and wants to join forces to take the fight directly to him.
Astaroth is over 300 years old. He learnt to transfer his consciousness to different physical bodies, prolonging his life. Revan believed that since this Sith empire were the survivors of Naga Sadow's empire from the Great Hyperspace War, the key to defeating Astaroth may be found within the teachings of Sadow himself.
Revan discovered that Ajunta Pall's blade is said to undo immortality, but only if the energy of the blade is harnessed by the dark side source that the Sith Lord you mean to kill drew their power from. In this case, Astaroth drew his power from Sadow's holocrons, before the moon was taken by Revan's forces.
Revan believes that he or she cannot kill Astaroth, and only a wound in the force like the Exile can challenge him, as the wound hasn't fully healed and the Exile still has that force god like ability. That's right Revan fans, Revan claims the Exile is more powerful.
Revan plans to direct his or her fleet in the final space battle above Dromund Kaas, while the Exile storms the citadel to confront Astaroth in the throne room. Revan wants you to help the Exile get to the citadel, then fight off the waves of Sith who try to get to the citadel entrance to protect it.
You go to Dromund Kaas and fight your way to the citadel with the Exile, while Revan commands his or fleet in the space battle above. Revan's legendary tactical prowess is needed to defeat Astaroth's main fleet, otherwise all would be lost.
You get to the citadel entrance and stay behind, protecting it from the waves of oncoming Sith. Meanwhile the Exile, armed with Ajunta's powered blade, fights his or her way to the throne room to challenge Astaroth in a player controlled battle.
While that is going on, Revan is confronted on his or her command ship by a Sith Lord who snuck on the ship. In a player controlled battle, Revan must defeat this Sith Lord, then resume command of the space battle.
The Exile manages to wound Astaroth with the blade, weakening him, but cannot defeat him. Astaroth begins overpowering the Exile, mainly with force lightning, to the point where the Exile is crippled and calls out to you via his or her special ability to form connections with others, to come and help him or her defeat Astaroth.
You arrive at the throne room and defeat a wounded Astaroth, who can now be killed permanently. The Exile is incapacitated during the battle. Following the defeat of Astaroth, the space battle concludes, with Revan's forces triumphing.
Okay, now for the endings.
Ending 1: LS Revan, LS Exile, LS PC: Revan goes to the throne room to meet up with you and the Exile. You're all Jedi, and naturally want to get the hell out of Sith space and go back home. Revan orders you to order your forces to attack the Revanites. They are the last Sith that stand in the way of peace.
The Revanites come after you for betraying them and to their shock, Revan and the Exile help you attack the Revanites and escape the citadel on a small ship. The space battle is won by the Jedi, the Republic and the Mandalorians and this is where we'll see Revan reunite with Bastila, Carth, Canderous and so on.
They obviously want to know what the hell happened and what Revan has been doing all this time and Revan says it's a long story, fade to black. Fast forward to the future and there are big celebrations going on throughout the galaxy, like in Return of the Jedi.
Ending 2: DS PC: Going dark side means killing Revan and the Exile, either because they're Jedi, or because they're a threat to your power. You kill a wounded Exile in combat in the throne room, then order your forces to attack Revan's ship while his or her guard is down and do what Malak couldn't do - finish the job. Of course, there will be a few angry Revanites who attack you, but they are no match for your power. Once you crush some opposition, the other Revanites won't dare to challenge you and therefore you will be seen as the new emperor of the Sith.
Ending 3: This one is where you're light side, but one of, or both of Revan and the Exile are dark side. If the Exile is dark side, you fight the Exile in the throne room, and try to redeem the Exile. If you succeed, the Exile returns to the light and if not, you have to kill the Exile. Same with dark side Revan, except you don't confront Revan alone, as Revan is more powerful than you are. You confront Revan with a team of Jedi and end up redeeming or killing Revan. So you still get the happy ever after ending, it's just that it may be without Revan and the Exile there to celebrate with you.
The end. Or if you can think of better endings, feel free to share your ideas..