Why?
That is the question Castiel asks himself before every decision, every choice, every action. Because now he knows – there has to be a reason for everything. After so many years of blind obedience, it's an innovative idea; innovative, yet necessary.
Because now he knows – nothing is as it seems. What is right doesn't always seem to be. Now he knows – good isn't perfect. Sometimes it messes up.
But that doesn't mean it isn't still good. Doubts don't make you worse. Only… different.
Now he knows.
And it's better that way. It was hard to admit – especially to himself – that he is different, and it's fine. He rebelled against heaven, and it's fine. He risked everything, and it's fine. Because it was worth it, and it was right. Isn't it what it all comes down to? Making sure the right thing is done?
And he was so afraid of falling. He was always the most obedient angel, the most level-headed angel, the most clever angel among his friends, brothers. Falling was worse than death in his eyes. Now, things look so different. Now his friends are two brothers in soul, who he never had to prove himself to continuously. Castiel chose a side.
Because now he knows.
Not that it's all sunshine and rainbows. Every day is a struggle, between what he has known his entire life, and the new life and principles he was forced into. He had to rebuild his judgment right from scratch, by the undeniable influence of his new family and the new reality that was formed around him. He adjusted himself for his new position and as hard as it was, it felt right, and that was all he needed. He often wondered whether he was more human than angel, now that he belonged to "Team Free Will", and if it mattered to Sam or Dean. He didn't want to let Dean down. He was looking up to him.
Because now he knows.
That there's something beyond. And it isn't God anymore, but something deeper, as strange as it sounds. Something worth fighting for. For this he rebelled against heaven, for this he risked it all.
The truth.
It is everywhere, guiding the way and lighting up everything. Because now Castiel knows. The truth, about everything. About himself, about good and evil, about the world and about what's right and what's not. Behind every decision, every choice and every action – lays is a truth.
And it's worth every doubt.