After ten years, he hated smiling. For smiling meant that one of them was leaving. Smiling meant that he had to fake thinking everything was fine.
Fake thinking that we were winning the war against the Millifiore.
Fake thinking that they were ever going to come back.
But he knew that if he didn't smile, than they would lose hope. That they would start to worry about him. He used to like smiling. But now, when he smiled it meant that he was lying. Not only to himself, but to his friends and allies. So, little-by-little, he stopped smiling.
Like really smiling.
And his Guardians didn't notice. They didn't notice that their once happy, naïve and carefree Sky, wasn't happy anymore. They didn't notice that he started sending them out on more and more missions. So when he started locking himself in his office for hours-even days- on end, no one was around to notice.
So when he stopped eating enough, no one noticed.
When he collapsed from over-working, no one was around to help.
And he was fine with this, for he knew that if they knew that he was this weak, they would stop to worry about him.
So when he calls his Cloud, no one thinks of it.
But during that meeting, the Cloud finds out just how lonely the Sky is. But the Cloud cannot stop it, for he knows that it is to late for the Innocent Sky to be pulled back from the abyss.
So on the Day the Sky died, no one was their except the Cloud, who knew not to stop it. His job was to wait, and watch and listen, until the Sky could come back. And he carried his body back to the base.
The cloud still remembers their faces, as he carried the Skies small body into the base.
And he doesn't regret anything.