The Return of Melkor (Later days church of Morgoth)

[Metus_of_Morgul]

Lets see,Melkor the first Dark Lord was outside of the whole world,in the void,and this was guarded by some...ones..

So it is possible that the guards were there in case he finds a way out?
Certainly he was not killed or something,you cant kill a Valar how ever deep he fell...so there must be a possibility that He could return..
I bet Sauron,even if he had won the war of the ring would not do anything to return him,that would make him 2nd in command,and he would not like it.
But for those who remained...for it is said that the evil these dark lords did will never be totally cleaned,until the foundations of Arda are re made...
So in the 4th age,we still have somewhere in the far ,far east 2 wizards,Alatar and Palando who probably turned to the dark side (because Sauron gave 'em chocolate) and had enough time to study the dark arts,even maybe to open a vortex which could be used to free the (one true) Dark Lord...?