The Tears of the All Father.

Have you have wondered why, if they gods exist, and they are benevolent, then why do horrific things occur? Why do they not stop it? If they cannot, are they truly gods? If they will not, are they truly as kind and good as we believe?
Sit, then, and I shall tell you the tale. The tale of why the gods smile no longer upon Midgard.
The tale of The Tears of the All Father.

Long ago, it had been the custom of the Aesir to walk disguised among men. It was well known that Odin did this, but the other gods took after his fashion, and would cloak themselves in the skins and clothes of mortals, and thus walk amongst men unhindered.
Through this, the Aesir remained knowledgeable about the workings of the world of men.
Now, it came to pass that the politics of the mighty nations of Midgard became greatly twisted. Through treaty and alliance, a twisting web of allegiances stronger that steel or blood was being woven by the powerful houses of the land.
This much troubled the gods, as ties of such strength between nations of such nature as these would inevitably lead to conflict.
Such a web was cast, too, that were any allegiances called upon, there was little doubt among the wise that the entirety of Midgard would be dragged in by these bonds.
The All Father then declared that all should sever their allegiances with the nations of Midgard, as he foresaw a mighty conflict upon the horizon, and hoped to spare as many as he could from it.
With reluctance, the Vanir and Aesir did so, and so did the Elves, both Light and Dark. With this, the Jotunn were convinced that Odin's actions held no treachery for them, and did as he had asked.
Midgard was to reap the crops it had sown, and perhaps it would be enough to shock them away from such actions in the future.
Or so Odin hoped.
So it came to pass, that one man tripped the snare that tore all Midgard down into war. One man slaying one other man for reasons most could understand.
Odin watched, as Midgard began to tear itself asunder.
He sent out the Valkyries, to take a full half of the slain, as was his right as All Father. As the maidens returned with the slain of the battles, Odin was shaken to his core.
He had not expected so many.
He stood at his seat of Hlidskialf, and gazed from it upon the War of Midgard, for it subsumed the entirety of that world, as Odin as foreseen, and he wept.
For four long years he watched, and for four long years he wept.
Only once did he stand, for the first of the four Yuletide days, when it seemed for a moment that the war would halt, but the next day found the grim All Father sitting and once more gazing out, weeping twice for each lost soul from his one eye.
Day by day, the Valkyries brought half the slain, as was the way. The ranks of the Einheriar swelled by near fifteen thousand thousand, in those days. Seven hundred and fifty thousand score slain souls feasting in Valhalla.
It was the the evening of the Tenth day of the Eleventh month of the final year of the war that Odin once more stood. The lake of his fallen tears splashed out from his lap, and caused a mighty river to form, flowing down through Asgard.
"Enough.' He cried out. By hand, he closed each of the doors of the golden hall. Five hundred and twenty doors he closed, still weeping twice for each soul slain upon the battleground of Midgard.
Having closed the doors of his hall, he freed the Valkyries from his service.
It was to Himinbjörg, the dwelling of Heimdallr, who guarded the Bilröst bridge between Asgard and Midgard, that Odin next went.
Heimdallr looked on in astonishment, as Odin strode without warning nor invitation through his hall, and, grasping the gate that lay open to the Bilröst, and thence to Midgard, slamming it shut.
"Enough." Odin declared, the anger in his voice shaking Himinbjörg, and breaking the gates so they were no longer able to be opened.
In silence, he bid the gods gather at the Thing, whence they did.
Once Tyr had sat and opened the gathering, Odin spoke.
"For four years, I have watched a mighty slaughter. For the last four years, the men of Midgard have fought brutally and needlessly against each other, slaying more I would ever wish to again see. I have lost all hope in men." As he spoke, the other gods were troubled to hear this, but none wished to speak out, for none of them had watched the War of Midgard as Odin had.
"I am closing Midgard."
As Odin declared this, there was much talk among the gods, which he silenced quickly.
"Upon the tip of Gungnir , I swear this. No man from Midgard shall leave that world without my leave, and likewise none may visit Midgard without my leave. This shall stand."
Having sworn his oath, Odin turned, and left the Thing.
As the other gods bickered and complained about Odin's oath, and Tyr forced order upon the gathering, the stream of Odin's tears began to trickle down to the edges of Asgard.
The millions of drops fell into Midgard, a rain filled with pain and horror, and all who found themselves caught in the shower recanted violence without exception.
But Midgard was to remain isolated. For the All Father does not make Oaths lightly, and nor does one break one made upon the tip of Gungnir.