Rayden

150 million years ago, an Elder God named Shinnok coveted the Earthrealm and sought to take it as his own, defying his duties as an Elder God since Elder Gods are supposed to remain out of mortal affairs when possible out of fear from awakening the One Being. A great battled ensued where a great deal of life went extinct on Earth, but Raiden was able to defeat the Elder God and he was caste into the Netherealm.

At some point he was appointed the protector of the Earthrealm by the Elder Gods. He took his duty seriously and aided Earth's warriors as much as possible, giving them advice and guidance since he wasn't allowed to interfere directly.

Before the current Mortal Kombat tournament, Raiden became aware that Sub-Zero was hired by Quan Chi to steal a magical amulet once belonging to Shinnok. Raiden appeared before Sub-Zero and informed him of his folly and gave him the chance to redeem himself, offering him guidance and later saving him from Shinnok's grasp.

When the Earth warriors defeated Shang Tsung and Goro in the 10th Mortal Kombat tournament, Shao Kahn, being a former champion, challenged Liu Kang himself. However since Shao Kahn is not allowed entry into the Earthrealm, the Earth warriors had to venture to Outworld, Shao Kahn's domain. Raiden went with them, however the Elder Gods made him give up his godhood to do so. Raiden and the Earth warriors would come to learn that Shao Kahn had tricked them and when Raiden returned to the Earthrealm he regained his power and protected many warriors from getting their souls taken by Shao Kahn, allowing them to fight back, but Raiden himself couldn't help any more since the Earthrealm was merging with Outworld.

After Shao Kahn's defeat, Shinnok attacked the Heavens with his Netherealm army. This time Raiden needed the aid of Earth's warriors and together they battled against Shinnok in Edenia. Raiden was once again able to defeat Shinnok and the Elder Gods decided to make Raiden an Elder God. But as an Elder God he could no longer protect the Earthrealm, so he appointed his younger brother Fujin to watch over the Earthrealm.

As an Elder God he witnessed Shang Tsung's and Quan Chi's advance to conquer the realms, but as an Elder God he was only able to watch. Realizing the true threat if the two sorcerers go too far, he gave up his position as Elder God to ensure the Earthrealm's survival and gathered various warriors to aid him. Him and his warriors found the sorcerers but had to battle their Tarkatan hordes, getting killed the process. Raiden confronted the sorcerers and challenged them to Mortal Kombat. While obviously superior, Shang Tsung cheated and their combined might was eventually able to overcome the Thunder God and he was defeated, and then they turned on each other. However the Dragon King had arrived and Raiden and the two sorcerers attempted to combat him, but he would not fall, so Raiden focused his godly energies and blew himself up in order to defeat the Dragon King... though badly hurt, the Dragon King survived.

As a god however, Raiden was not truly dead and he reconstituted himself. Raiden was aware of a mortal named Shujinko whom was tricked by the Dragon King into reviving him and became enraged, deciding to ensure Earth's protection with force and reanimated Liu Kag's souless corpse to be his enforcer, killing anyone Raiden saw as a threat to the Earthrealm. The new darkness that enveloped Raiden would catch Shinnok's eye and he appeared to Raiden offering a partnership, agreeing to help Raiden ensure Earth's protection. Raiden didn't trust Shinnok but agreed so he could keep an eye on him.