Rain/Current Timeline

"I am a son of Argus! I was not merely declared a god by befuddled commoners, Buluc."

- Rain to Kotal Kahn on their godhood.

Biographies

 * Mortal Kombat (2011): "A refugee orphaned by Shao Kahn's conquest, Rain grew up under the protection of the Edenian Resistance. An exceptional fighter, he soon rose through their ranks. As his reputation grew, so did his arrogance. When Rain demanded leadership of the Resistance forces, he was refused. Infuriated, he turned against his rebel comrades and betrayed them to their sworn enemy. In payment for this treason, Rain was promised his own army by the emperor Shao Kahn. Power would be his - no matter the cost..."

Mortal Kombat (2011)
In Mortal Kombat (2011), the official reboot of the series, which covers, and alters, the past events of Mortal Kombat 1-3, Rain was introduced as DLC. His original backstory as an Edenian orphan is retained, although in a modified form.

He bore witness to the invasion of his home world at the hands of Shao Kahn. During the chaos that ensued, Rain was smuggled away while his father stayed behind to perform his duties as a general in the Edenian army. Edenia's armies were crushed in the Outworld invasion, and Rain's father was subsequently killed by Kahn himself.

After that, he was rescued and raised by the Edenian Resistance following his adoptive father's death. He trained hard under their tutelage and turned into an elite, but arrogant fighter. He served the Resistance well for many years and he was denied his own command. Infuriated, he betrayed his own brethren and joined his mortal enemy, Shao Kahn, who promised Rain leadership of his own army.

Mortal Kombat X Comic
Though unseen, Rain was revealed to have joined Reiko and Mileena in their war against Kotal Kahn. Rain proves to be an essential part of Reiko's plan in their ambush of Kotal K'etz and his forces, using his control over the weather to block out the sun, weakening the Osh-Tekk's powers before his confrontation with the Shokan Prince Goro.

Rain makes his first physical appearance standing alongside Goro as the Shokan rallies the Red Dragon soldiers. Upon spotting Kotal Kahn approaching, Goro orders Rain to once again manipulates the weather by blocking out the sun to deny Kotal Kahn his primary power source. Rain complies and summons clouds to block out the sun.

But Kotal Kahn, armed with the power of Blood Magik granted to him by his Kamidogu, was not affected and calls down a beam of solar fire to burn the Edenian alive. Rain is last seen on the ground, badly burned but groaning in pain, indicating he may have survived his injuries, but his current status remains unknown.

Mortal Kombat X
Rain returns as a non-playable fighter in Story Mode.

When Kano gave Mileena Shinnok's amulet as a weapon to be used against Kotal Kahn, it was Rain who suggested to her to use it despite her hesitance, knowing that each use would slowly kill Mileena while the civil war weakened Kotal Kahn's forces, allowing him to eventually steal the throne of Outworld for himself. Rain also learned of his divine heritage as the lost son of Argus and began to declare himself a god.

In Kotal Kahn's chapter, Rain accompanies Mileena, Tanya and their Tarkatan forces as they follow Kotal Kahn's carriage, luring the emperor into a trap with Kano's help. After Mileena orders Tanya to attack Kotal and his forces, Rain urges Mileena to use Shinnok's amulet to kill Kotal Kahn. Rain stayed by Mileena's side during the attack and watched on the side-lines as Kotal Kahn knocked Mileena off the rooftop they were hiding on with a blast of solar light.

When Kotal Kahn brought up Rain's divinity in disbelief, the Edenian was quick to trap the emperor in an orb of water while reminding him of his own claims to godhood as labeled by Earthrealm mortals. Kotal escaped and questioned Rain's intentions while charging at him, but Rain teleported behind Kotal and dropkicked him off the roof-top and onto the street below, confronting the emperor for battle as he prepared to teach him the difference between pretension and true godhood.

Rain lost his battle against Kotal Kahn and was nearly executed by the gunslinger Erron Black, only saved by Mileena's intervention, allowing Rain to retreat by teleporting away. When Mileena failed to kill Kotal Kahn with Shinnok's amulet and was briefly stunned by the amulet's energies, Rain teleported back to collect her before fleeing again.

In D'Vorah's chapter, Rain is confronted by D'Vorah and Cassie Cage as they storm Mileena's camp in the Kuatan Jungles. When D'Vorah reveals she knows of Rain's desire for the throne of Outworld, the son of Argus reveals his deception of Mileena, revealing it was he who devised the plan to steal Shinnok's amulet. When Tanya grabs Cassie, Rain attacks D'Vorah, intending to kill her, but loses to the Kytinn. He is not seen again for the rest of the story, leaving his fate unclear.

Endings

 * Mortal Kombat (2011): (Non-Canonical) "Shao Kahn had used Rain to crush the Edenian Resistance, but had not granted him an army. For this betrayal, Rain drowned the emperor in his own blood. A grateful Raiden thanked Rain for eliminating the emperor and saving Earthrealm. His heroics were befitting of a son of Argus. Rain's lost heritage was a revelation to him. That he was a direct descendent of an Edenian god, proved his superiority. Power was his by right. His divinity confirmed, Rain's path was clear. He would use Shao Kahn's army to rule not just Outworld, but all the realms. To Raiden's surprise and horror, Rain's first target is Earthrealm."

Mortal Kombat

 * Lost son of Argus.
 * Adoptive son of an Edenian general who was killed by Shao Kahn.
 * Rescued and raised by the Edenian Resistance following his adoptive father's death.
 * Betrayed the Resistance when they refused to make him their leader and joined forces of Shao Kahn.

Mortal Kombat X Comics

 * Joined Mileena and Reiko against Kotal Kahn.
 * Blocked out the sun with his control over storm clouds to weaken Kotal K'etz.
 * Attempted to repeat the tactic on Kotal Kahn but was burned alive, barely surviving his injuries.

Mortal Kombat X

 * Joined Mileena and Tanya in ambushing Kotal Kahn with Kano's aid.
 * Fought Kotal Kahn and lost.
 * Nearly executed by Erron Black but saved by Mileena.
 * Revealed that he was behind Mileena's plans and planned to steal Outworld's throne.
 * Fought D'Vorah in the Kuatan Jungles after their camp was raided but lost.