he gets killed in Armageddeon, after sacrificing himself to prevent the apocalypse. Its a noble and tragic deed, which redeems him.

Why wouldn't Raiden return? This is actually a good game to put him in. I'd like to see where he goes now that there's a new world of characters entering MK for MK8.

CHEERS!

Well I have an Idea as to how corrupted(neutral) Raiden can be restored.

During the constant battles for the earthrealms protection,Raiden finds it constraining to fight each threat at a time,while the new guardian Fujin only intervines if someone actually dangers the earthrealm.Raiden decides to deal with the enemy via a preemptive attack.
He openes the portal to outworld and he goes through,When he emerges in outworld he winds up in front of a weird scene-Shinnok is having a conversation with Onaga.The dragon king gives Shinnok an amulet resembling the symbol of the elder gods.
Raiden realising the amulets power reveals his presence by hitting unprepared onaga with a lightning (now without the power of kamidogus is blasted to the ground),He turns to shinnok who jumps into the open portal.
Raiden follows to the netherealm.
As he exits the portal he is attacked by Noob ,weakened by a stealth attack Raiden is overpowered(but not without hard effort).Noob steps over the exhausted thunder god for the final blow when he is attacked by the deamon hunter Ashrah,who was following noob's trail.As they fight the tired ninja is no match for a demon like Ashrah so he retreats.
Ashrah then approaches raiden who is already on his feet,she feels the darkness in him greater then in any demon.
She attacks him with Heavenly light which blasts Raiden into the nearby ruins as he tries to get up he is pinned by lightning blast.she then stands over Raiden and impales him with KRISS.
Unlike the effect on demons which are mostly driven by evil,raiden is merely corrupted and his devine power protects him from destruction,but he vanishes.
Ashrah feels the effect-Now she is capable to freely leave the netherealm.
Raiden finds himself back in the earthrealm purified from corruption,Light sided again.
(as it was set pure soul cannot stay in netherealm so this is the reason he vanished form realm)
Well what do you think?