Re:BIRTH - The Lunatic Taker

Reiji isnt a saint and has a lot to work on but Ayaka isnt one either. The keyword I see is "lunatic" meaning her way of thinking whether she knows it or not is still wrong. It goes back to the old saying. "Its hard to see how deep in a hole you are." She has never once thought that what she was doing is wrong. "I took the life of a person who is as precious another as Reiji is to me, but I protected him. Thats a disturbing and dangerous way of thinking. A stronger individual sharing Reiji's mindset(horrible example but he has it nonetheless) would at least consider the alternatives, even if the result is the same.

Reiji definitely isnt off the hook. chapter 24 was a complete f*** up. She needed a loving partner to awaken her to the flaws in her character painlessly. That was completely abrupt and abrasive. I hope this latest move was an act(really stretching it) to help her realize her tendencies and not some "fraidy-cat" attempt to get rid of her. The world isnt full of rainbows and butterflies hes been sheltered to believe. Ideally, he should get strong enough to protect her and return her feelings and care she's given him all this time.

I paid close attention to the column about moral absolutionism. While personally I find myself between the line of absolute and non based on the acts. For example, killing is an absolute while lying is non. Whats happening here is that Ayaka believes shes right no matter what she has to do in order to save him. Her actions are that of an automoton carrying out an order. Without the thought beyond the implication of her actions there is no "good" in her excuse.

When he threatened to kill himself, I pretend that I was reading a manga about peter pan, started clapping hands, and started thinking "if I just believe hard enough....."

especially after he realizes that due to his "morals" he pretty much tried to kill his sister

They succeed in killing Ayaka, T_T, and we get to see how Renji and his "morals" deal with that

She is using him as a crutch to allow her to kill? I believe that is the very opposite of the situation. In the first chapter, in the first couple of pages, the (I assume) mother says "As long as you love Reiji, you will..." This, coupled with the revelation that she is a natural psychopath (you have to take this as a fact within in the manga, even if you might disagree with it in actual life), makes it more apparent that Reiji is her barrier against being a murderer. She has no morals in regards to killing for which she needs a greater amount of incentive to overcome; basically, she has the mentality that killings things is okay, even on a whim. I would suspect that if the author were to shed some light on her history prior to Reiji, it would be full of standard mass murderer aspects; killing small animals, hurting people, possibly hurting herself (I think the way she treated the dead puppy in the other flash back was a reference to this kind of mentality). That kind of past would also explain the first few pages of the story.
Then at some point in her childhood she would have been caught engaging in one of the acts above, and would of course been told that she shouldn't do things like that, by a parent or some authority figure. I can't think of the best way to word this, but this would put a societal and logic-based block to her actions (she doesn't feel that what she is doing wrong emotionally, but rather she understands that other people think and feel that way, so she should act like it too - as a child, it is normal to model your behavior on others).
Then you add in the Reiji factor, and now she has something to obsess over that allows her to seem normal to society (she can focus on motherly/sisterly feelings and the desire to protect rather than developing the psychopathic side of her). An extremely weird sounding but plausible scenario for her would be "Oooh, a bird, I wonder what it would do if I choked it... Wait, I can't, I have to go make dinner for Reiji" and in that way she would be able to live a normal life.
But, this is all in normal society, right? Then they get thrown into taker-society. Now all those people who should be telling her not to kill others are suddenly telling her she should be killing. Furthermore they are trying to kill Reiji, which means that now both the society she is in and her obsession with protecting Reiji are complementing her psychopathic feelings. Reiji, however, is stubbornly sticking to the ways of people in the normal society, which is complicating things for her - she wants Reiji continue his relationship with her in the same way, yet she doesn't want to make him change, yet she feels like he needs to in order for her to fulfill her protection of him. The way she handles this in the future is a major focus of the manga; as she said in chapter 23, she could cut off the normal relationship between the two, and force him to accompany her into the new taker ways of society (a very possible route, though I'll not try to predict who changes who or what happens, because I'd rather not have 'my idea' of the story to conflict with the author's), she could allow him to be himself at the cost of himself (extremely unlikely, both in terms of her psychology and the manga), she could throw away her obsession, she could go insane, etc.
So anyway, there's Ayaka; now for Reiji.
Reiji, mostly thanks to his sister, has lived a very protected life; this has allowed him to easily foster "lofty" opinions about the world, and to believe in them. When he is thrown from his protected life in normal society to the taker's society, which goes absolutely against his principals, he is understandably horrified. Normally, he would have to choose between upholding his lofty principles and dying or revising them to live; thanks to the way the plot has unfolded so far, however, he has been allowed to live with his lofty principles (the existence of the angels, his sister's protection, and the fact that all of his enemies conveniently die of other causes when the decisive moment comes).
This exceedingly forgiving plot ends abruptly in the last arc (though not the way it would without his sister), when his sister finally decides to stop counting on luck and do the job herself, with unfortunately disastrous results. Until his sister crossed the line into the taker society, he didn't have to, because she also kept him alive, but now that she has, he is essentially alone being "normal" while everyone else has adapted. Now, his feeling of denying the takers also includes denying his sister, which conflicts with his emotional attachment to her.
At the very beginning (immediately after the event) he is despairing because he feels he is now caught up in the taker way of life. To deal with this, he pushes the blame solely to his sister. Then, after he's told that shes psychopathic, he feels sorry because its not her fault that she was born that way (I'm not saying she's guiltless, don't worry), and he goes back to reconcile. He can't (so far, at least), however, which I believe is because he realizes that she doesn't and can't feel the same guilt that he does, when she was the one who actually "did the act". Then Natsuki is nice to him in his moment of weakness and he clings to her, which really isn't going to help him in his sister's eyes. I suck at getting to the point.

In the eyes of normal societal logic, Renji is good and Ayako is a murderer, and its plain and simple.
In the eyes of the taker's societal logic, it is survival of the fittest, Renji is prey, and Ayako is a top predator, and that is also plain and simple.
Feelings are separate from logic, however.
Renji views things the first way, but he is not a cold, emotionless body of logic, and so his feelings towards Ayako are conflicting with his logic and that is his problem.
Ayako views things the second way, but she has obsessive feelings towards Renji, so her problem has been trying to let him be himself and not hate her while also protecting him from his actions (presumed by those in the taker society to be foolish).

There are three influences to an opinion, society, emotion, and fact. Rinroken, you feel people are too emotionally attached to Ayako, and therefore pointing the blame too much at Renji, but your view could also be seen as too based on societal common sense. Unfortunately the third influence, fact, has nothing to do with right or wrong (only true or false), so it is impossible to derive fault through only fact.
Just to clarify, personal opinions are societal opinions too, because a group of one is still a group (furthermore, I doubt there is a single opinion which only one person in the entire existence of our world has had, though its theoretically possible for someone to have a unique collection of opinions)