Nana is a mist who was deeply hurt in her youth. All she is, all her resources and misdirection and illusions are dedicated to protecting herself. Iemitsu was safe, stupid, delusional, devoted to the idea of love and gallantry. He was also willing to take a no for an answer; she tested, to be sure. Thus he was perfect for a girl grown into a woman with walls miles high and camouflage so good you would never know who she really was, would never even know what you were seeing wasn't the truth.
Everything was fine. Tsuna was the light of her life. Iemitsu was absent, and that was good - she'd tolerated him, but now she didn't have to, but was still protected as a married housewife in suburbia.
Tsuna was special, he held the sky. They would play cat's cradle with sparkling threads of light, would practice throwing things with little balls of flame. Nana would throw mist flame and Tsuna would change it then she would change it back and so on. She would tell stories and teach him about the world - the names of thing, letters, and numbers - with illusion.
Then her safe, idiot, absent husband came back and shattered everything. He hurt her Tsuna. Made him dull and cold and slow. Crippled. That loathsome old man sealed him.
Why? What gave him the right?
Men were always dangerous. Either they were blind, stupid, and cruel with it or they were simply cruel. Taking, always taking, always entitled and righteous and vile. How could she have forgotten? Just because Iemitsu had seemed so toothless and safe - hah, what delusion - didn't mean he actually was. He was still a man, after all. And she was still married to him, he was still Tsuna's biological father and had legal rights to them both. And he had done this to her Tsuna, to her. Why, why, why? (And that night she didn't say no, didn't dare. But it hurt and if he had ever loved her it should have been obvious from her entire body, but in the end he didn't care.)
Why, indeed? Well, she was a mother. And Iemitsu was gone all the time. That gave her some leeway. And she could be strong when she had to be. Tentatively she began stretching her flame. Mist was construction, after all. She would make a key to unlock the seal, a dagger to pry it off, a flame to melt it away. Her Tsuna would be whole again.
And, again the question why. Or rather the mystery of her husband. A mystery that she had not cared about when she had thought him harmless. She would not be making that mistake again. She searched the house, thoroughly, and found papers, guns, knives, money, passports. Some of it spread out, a lot of it in a big box, a stash, buried in the garden, under the flowerbed he had put in when he bought the house.
It was worse than she had ever feared. Mafia. Vongola. The underworld. Blood, power and terror. She knew of the mafia through the yakuza - though the yakuza was mostly a joke to the rest of the criminal world. Well, Japan's protected status and relative obscurity in mafia circles would only help with what she was planning.
She succeeded in getting the seal off of her son, though it took months before he was back to normal again. Normal being sweet, curious and shy of adults but not timid. Her husband was a fool. Of course his son had been wary of him - he was a stranger. Many children were cautious around unknown grown-ups, but that was perfectly normal. Then Tsuna had been hurt and had changed. She had heard Iemitsu talking to that vile old man about her son. How he was cute, but too soft, weak. That perhaps he wasn't suited for the family business.
Now that Nana knew what the family business was, well, that just meant more leeway. She was widening the hole, and soon she and Tsuna would slip away. They couldn't stay in Namimori. They were too visible here, targets for assassins and bound and hemmed in by expectations of how Iemitsu's airheaded, civilian wife and useless son should act. But she was a mist, her special boy was a sky and both of them were pure as spring water and powerful as the very ocean itself. She made the illusionary constructs, wove them hard and fast and lasting. Tsuna helped anchor them with his flame, helped give them a presence that read as alive to any watchers. So what if the constructs weren't the best conversationalists, that the Nana clone seemed shallow as a drying puddle, and that her 'son' barely spoke? That was what Iemitsu thought of them already.
Then they were gone, evaporated, blown away on the spring breeze like morning mist. It had taken less than a year for a civilian housewife and her six-year-old son to outsmart the most powerful famiglia in the underworld. They moved north to Hokkaido, to a small village by the sea, close to the mountains. This was where her mother came from, the useless woman. More importantly, this was where the rest of her family lived, and they were of a different quality altogether. Many of the people here had flames, many of them mists.
It was known that Ito Maki and her son, who had recently moved to the small seaside Hokkaido village, really were of the Sato family, but no one ever spoke of it. Sawada Nana and Tsunayoshi simply became lost in the mists, in layers and layers of subtle, unimportant, misdirecting vapour.
Nana continued to monitor the situation in Namimori through the clones' eyes. Sometimes she couldn't help but test the waters a little. She went out more, tried to get friends, to go out of town for a little holiday with her son. Inevitably she was stopped by freak circumstances. She showed interest in a man, who disappeared while her clone was discouraged from infidelity by way of a mist-net. She deliberately walked into an ambush by hitmen from a rival family. She pretended to panic and was hit on the head and then told she had fallen down the stairs when she woke up in hospital. No, Iemitsu didn't want his wife aware.
Thank any and all higher powers she had gotten out when she did. Her blunt-clawed husband had subordinates, mind-control and the long arm of the illegal. And he wanted her vapid and normal and loving in his absence.
Then suddenly that wasn't enough to protect them anymore. Famiglia was more important, more real than the make-believe dollhouse he had allowed them. The last Vongola heir had been murdered and now he had a use for his cute, useless little Tuna-fish.
The hitman Reborn was sent to tutor Tsuna. The years the clones had been in action had been an exercise in dodging and caution, but they had managed. The first bullet to the head and Sawada Tsunayoshi popped like a soap bubble, leaving a faint waft of mist and sky. At the house Nana's clone laughed. Then Reborn came tearing in.
"Sawada Nana and Sawada Tsunayoshi are no more. You are too late. I've won," the thing that wasn't Iemitsu's wife said. Then the mist-contruct popped, too, right in his satisfyingly angry and confused face.
Nana had been careful. There were no papers connecting the clones to her and Tsuna's new home. And she'd deliberately made her laugh cruel, made it sound as if she was a he, using ore instead of atashi. Hopefully Iemitsu would think that they had been killed.
Sawada Nana and Sawada Tsunayoshi were indeed lost. Only Ito Maki and Ito Hajime remained.