It had only been a few years since Malekith's attack when Thor discovered somethin rotten in the realm of Asgard. He came home unexpectedly and unnannounced. He told no one of his arrival. He sought out his father and did not find him in his chambers, so he went to the sleeping room.
It was locked.
The sleeping room was never locked.
And this was when an inkling of something being not-right had entered Thor's mind. He did not know why he felt this way, but his intuition for trouble had been fairly well honed growing up with Loki. He shoved on the door and it did not budge. This was not good. The sleeping room was usually guarded by sentries because if something went horribly wrong, someone had to be able to wake Odin. Only Frigga had known the means to wake him, but after Loki's departure from Asgard, Odin had trusted Thor with this knowlege as well. Just in case.
Thor took one single swing at the door with Mjolnir and it crumpled. The room was dim. Only a faint glow eminated from the sarcaphogus at the centre of the room. It should have been glowing brightly. Thor lit the torch by the door and discovered there was a lid over it. He cautiously examined this lid, walking around the perimeter, looking for signs of trouble.
There was a large amount of blood on one side that had dried dripping down the corner of the stone. He prepared himself for the worst and heaved the lid away. The golden light was blinding in the dim and he extinguished his torch. The All-Father appeared alive. Thor whispered the awakening words, knowing that the one on the throne was the imposter.
Then all hell broke loose.
As Odin strode to the throne room, his armies joined him. Thor's presence added legitimacy to this being the real Odin. He announced his intention to remove the imposter alive and reveal him publicly. And that is exactly what he did, Loki stripped of his disguise during the evening festival in the city square.
To those who did not live in the palace, Loki had simply disappeared after the accident with the Bifrost years ago. They did not know the malfunction was not a malfunction at all, and they did not know about New York. They did not know he had been returned in chains and then left in the dungeon to remain there, freed only by Thor's need for vengeance. They did not know of his false death on Svartalfheim. He had vanished. This was unusual, but he had been sequestered for years on a project of some scholarly importance many years before, so it had not seemed too odd and the throne had not sought to issue any statement to confirm or deny this belief.
When he was publicly revealed, the realm went into shock. Odin had been a little different the past few years, but not in a bad way. There had been more leniencey on some things, such as talking poorly of the throne and on youth defacing monuments of the royal family. The throne had been largely quiet, the citizenry left alone to live their lives without its interference. Most people had been fairly happy and the realm had prospered under the few reforms that had been put in place to facilitate more fair trade and fair labour, as well as the measures to create better lives for non-native born citizens who had sworn fealty to the realm. The difference in the king had been a willingness to change.
Odin's first reaction had been to declare every new law and policy created during his absence null and void, but his first day after doing so, hundreds of Aesir and citizens of Asgard lined up outside the palace gates seeking an audience. They all spoke of how the new laws had changed life for the better and he decided to let them stand. Loki, it seems, had listened to some of his lessons more closely than he had thought, and had built upon them.
One brave man dared to tell him, "Might as he was a traitor, your Highness, he wasn't a bad king. In some ways, he was even a good one. He sure had us fooled, he did such a right well job of being yourself, Sir."
After the third day of audiences, these mostly thanking him for reinstating Loki's laws creating a more equitable Asgard, he sent everyone away and did some thinking.
A soldier approached him, "One of the women won't leave, All-Father. She says you ought to know her family."
"Oh? Did she send proof of this claim?"
"She sends this." He handed Odin a scrap of fabric with an ancient insignia on it, "Says it belonged to her grandfather."
Odin studied it for a moment and let old memories float to the surface, "Send her in."
Not long after, a red-haired young woman knelt before the throne, "All-Father. Thank you for granting this audience. I only just heard."
"Heard what?"
"That Loki sat here in your place. I was in the counrty with my cousins."
"Your family was once quite prominent. Your grandfather fought with my father against Svartalfheim many years ago." He handed her back the insignia.
"Yes. But those battles are long forgotten and we have fallen to obscurity. Our families crossed paths more recently. I often studied alongside Loki when you sent him to the temple to learn from the manuscript illuminators."
"So you come to me about him."
"Yes. We were once friends. If possible, I would like to visit him at least once. Even a condemned man ought to know his friends still think of him."
"Perhaps. I will send for you once I decide."
She rose, then bowed deeply, "Thank you, All-Father."
"Before you leave- your name?"
"Iris."
"Go, Iris, and wait for my messenger."
She bowed again and left.
Odin returned to his chambers to think.