guilt [gilt]

  1. the fact or state of having committed an offense, crime, violation, orwrong, especially against moral or penal law; culpability.
  2. a feeling of responsibility or remorse for some offense, crime, wrong,etc., whether real or imagined.
  3. conduct involving the commission of such crimes, wrongs, etc.: to live a life of guilt.

Note: This page will only really make sense if you've played the game or at least gotten up to a certain point. I don't really feel like explaining the entire story in a page targeted at something else. Sorry! 

Living a life of guilt isn't something Mitsuru's father ever wanted for her, but she took it up still. And even he should have realized it was something he could not stop.

Upon finding out about the burden her father bears with the company and the actions he put into motion, Mitsuru bears that responsibility along with her father. She bears the weight of trying to change things for the better, all the while not knowing that her actions had, at some point, caused the worst to happen; caused chaos and world denomination to erupt. With the death of her father, Mitsuru ceases to function like normal and goes back to being Purely Business, as her own way to deal with it is to just be so incredibly busy that she doesn't have time to think about what a failure she is.

Because she's such a failure, and she can't stop thinking that way. She wasn't able to ease her father's burden while he was alive, and so neither was she able to save the life of the one family member she really had. So instead of talking to someone about it, instead of trying to ease her suffering and allowing herself to be sad; to feel grief--she makes herself so busy with her succession and father's funeral and other business that she doesn't have time to think about what happened. She doesn't have to think about how much she failed.

The guilt Mitsuru puts on herself is so great, even S.E.E.S. doesn't know how to help her at first--they just leave her to do business on her own. But she finally comes back, they start to really see the damage losing her father has done. And of all people, Yukari is the one to do something.

During their school trip, she takes it on herself to try and help Mitsuru in any way she can. Perhaps because she knows what Mitsuru is going through with losing a father, or perhaps because she finally sees the humanity and friendship in Mitsuru and simply wants to help. Or maybe shes gay-- WHO KNOWS! But she does help, and she is the one to help Mitsuru out of her bind.

Yukari: Hey, did you know that I used to live around here? After my dad died, my mom spent all her time throwing herself at random men... I couldn't stand to see her acting like that, so I used to come out here to the river bank to get away. My belief in my dad was all I had...
Mitsuru: Your father was only doing what he thought was best...
Yukari: Yes, but it was still wrong. So he fought to the end to try and make it right again. He never gave up. He believed Shadows were dangerous, and they needed to be stopped, even if it meant losing his life... That's why I fight. I want to eliminate the Dark Hour and fulfill my dad's final wish.
Mitsuru: Fulfill his final wish...
Yukari: That's all I—no, we, can do. ...Right, Senpai?
Mitsuru: Yes, I agree, Takeba... It's not over yet. Nothing has been decided. We must put an end to this. For the sake of my father... and yours.

During their conversation on one of their final days in Kyoto, Yukari is able to pull at what has really been bothering Mitsuru, which is a feat considering Mitsuru rarely opens up to anyone. She breaks down about how she feels responsible for her father's death—she feels it was on her to protect him, and she failed. She asks Yukari why she even bothers to continue remaining friends with her when they have no common goal to fight for. Yukari retaliates and lets Mitsuru know the harsh truth: both of their father's would want them to continue fighting. Yukari opens up to Mitsuru about her own struggles with her mother, and also about her father.

To see this in detail, please visit this page of my shrine for Mitsuru and Yukari!