Sakura
I don't think anyone knew about inner Sakura for a long while, 'cept for maybe Ino.
We did know about her obsession with Sasuke. She made that obvious.
But she was smart and she worked hard, so the chuunin and jounin overlooked her oddity.
It's not like ninja were supposed to be normal, anyways. It was good she could be so single-mindedly determined and dedicated, right?
The day Sasuke stumbled in through that gate and she raced to meet him first, I'm sure she got the surprise of a lifetime.
Though she must have known she was fooling herself to believe that he would come back whole. Sakura was smarter than that.
Instead, he came back dragging two bloodied heads.
Whatever warm greeting she'd rehearsed died on her lips, then.
And Sasuke trudged right past her glazed eyes and her gaping mouth, indifferent.
Because the bastard had done what he'd set out to do. Sakura didn't matter.
But Sasuke mattered to Sakura. He mattered more to her than he could have possibly mattered to anyone else. But Sakura was a strong girl. Probably even stronger than me.
It was about then that we began noticing inner Sakura.
She would be running my tests at the hospital, ranting about how I was always getting in trouble, when she would suddenly stop and start zoning out. It wasn't a lackadaisical type of zoning out, but more of a harsh, determined zoning out. Like she were concentrating real hard.
Normally, she would snap out of it within five to ten seconds and pick up wherever she'd left off.
Then she zoned out in the field for a minute, and someone died.
Sakura used to spend a lot of time milling around the streets of Konoha. Sometimes with Ino, sometimes with another kunoichi.
After Sasuke came back and she started zoning out, though, I didn't see her anymore.
Her parents requested surveillance of her. They wanted that Sakura out of their life. They wanted their Sakura back.
Didn't they have their Sakura?
I think Sasuke made her fall apart, and I think he knew it and just didn't care.
I think Sakura knew he knew and didn't care.
Whatever the case, Sakura's inner self was getting out of control. Instead of zoning out, she flew into rages for no reason. During them, she was beyond reasoning with. The only thing to do was stay well out of her reach.
Sakura knew she was crazy. She knew it and she hated it with every fiber of her being. She hated that her inner self was so violent.
She never told anyone that it was she, not her inner self, who was depressed.
Suicidal.
The fact that she couldn't stand her inner self only egged her on. She wrote a very nice letter to her deceased Sasuke-kun and a few to her closest friends, mentors, and family, which were found neatly stacked beside her.
Mine was so drenched in blood that I still can't read it.