First and foremost, when Yuri first created the battlefront, she wasn't a natural leader, even though Hinata says otherwise. She was brash, and pretty much roped anyone who she considered as a human with a soul. She didn't care what methods she used, as long as she somehow managed to gain a member of the SSS. In fact, she even kicked Hinata off the school building just for the sake of proving her point.

Throughout the series, and especially shown in Track Zero, Yuri shows that she will use whatever means necessary to achieve her goal of meeting 'god' and giving him several good punches. In fact, she even suggests that they should murder all the NPCs in order to force god's hand and make him show up. However, Hinata, the conscience out of the two of them tells Yuri that doing such a thing is demeaning, and so Yuri changes her tactics so that she doesn't do something as horrible as killing another person, even if they are NPCs.

Yuri also contradicts herself quite often in the series as well. She says that religion is just a thing that mankind created, yet she believes that there is a 'god', and even that Kanade Tachibana is an 'angel' sent from that god.

Another thing to note is that there are two reasons for being in the afterlife. The first reason is that they have things that they regret from when they were alive. In Yuri's case, she regretted the fact that her younger siblings died and she blames herself for her death, even to the point that she is unable to be tricked easily by Naoi's hypnotism. The second reason is because almost everyone has forgotten about the concept of 'love'.

And in both the anime and in Track Zero, the prequel, Yuri learns a lot. She starts off as a girl who does whatever she wants to get what she wants. She soon learns that she can't do anything on her own and that she has to have people to support her. She can't be selfish in order to attain her goal, and that's why a lot of people in the SSS have her back.

Yuri also learns that it wasn't entirely her fault that her siblings died; she was unable to do anything to help them, and it was actually possible that she would have died along with her siblings if the police didn't come. She also figures out that love is important to her. Not only does she love her siblings who died all those years ago, she cares a lot about the SSS members because she knows that they have her back. And she can trust them.

... Though she is slightly huffy about admitting that fact.

She also has many misconceptions about Kanade Tachibana (Angel) a lot throughout the series for many reasons. One, the first time she saw Kanade use Hand Sonic to take out Chaa, she considers it as a supernatural feat, something that no ordinary human or NPC could do. And because of that, she considered her as 'special' and gave her the nickname of 'Angel'. To Yuri, Kanade was their enemy, and only in the end when Otonashi finds out the truth (that Kanade was just using the resources that were already given in order to gain these new abilities) does she know that Yuri could really have been friends with her.

So basically, here's the short (and hopefully, understandable) version of how Yuri changed throughout the series. At first, Yuri was a girl who had lingering regret over the past, even though many years had passed since they died. In order to compensate for that loss in the afterlife, she decided to rebel against the so-called god who ruled over the afterlife, and this is what fueled her determination against fighting the laws and rules of life.

As a leader, Yuri was selfish and did whatever she had to in order to achieve the desired results, even to the point where she was hurting others (in fact, she plays beach volleyball on a place . Of course, this changed later on, as she became more and more understanding of others, though she does still do her own thing (for example, she blows people's chairs up because everyone is a complete idiot), but she isn't the type of person to sacrifice others, especially when it comes to the end of the series.

That's why Yuri's considered as the 'perfect leader' for the SSS, because she's someone that can be looked up to.

Of course, even though she has been accepted as the best leader out of everyone in the afterlife, she has made mistakes in the missions that she's been through.

Naturally, Yuri tries to come prepared, and she even goes to extreme measures just in case something goes entirely wrong - for example, she gets propellers when she realizes that her idiot brigade are too stupid to distract the class. She also gives Otonashi a walkie-talkie just in case something goes wrong. ... And things do go wrong.

Even so, she didn't realize that she saw the problems of this world wrong.When she made Kanade fail all her tests and get booted off the student council, what she didn't realize was that Kanade wasn't exactly the real problem in the afterlife. The fact that she had a misconception of how the world worked from the very beginning is what led her into making decisions prematurely, which led into making things a lot worse in the world that was meant to be for helping people.

Which means that sometimes Yuri over-prepares for certain situations. And sometimes she doesn't think about the consequences for her decisions, which leads to her mistakes. However, even with these mistakes, Yuri is always determined to stick to her team and to her friends until the end.

Sure, she did joke about death in the beginning of the series, and even more so in Track Zero (i.e: "You wanna die?!") and even doesn't care about hurting others in order to prove that either she's right or she's pissed off for some reason (i.e: Dehydrating the entire SSS as a penalty game), but near the end of the series she realizes that laughing about dying is like throwing away the concept that they were actual living beings, that they had actual lives.

After all, fighting in order to tell the 'god' of the afterlife is all what drove Yuri right until the end. She would do whatever she wanted until she reached that goal. However, that goal is never reached due to the fact that her lingering regrets began to fade away since she had really close friends who she knew cared about her. They were all important to her and she knew that they had her back just like she had theirs.

Long story short, Yuri grew a lot. At first, she was a brash, selfish girl who didn't care about anyone but herself. All she wanted to do was get more people (for her own personal reasons, not for anyone else's) in order to fulfill her mission, since it would be illogical to do something so big on her own.

She still had many lingering regrets which made her somewhat distant from other people, even though she did her best to not come off that way for the sake of others. In fact, she didn't even tell anyone about the huge regret she had from her life until Otonashi came along.

But she soon learned that people can be trusted. That love can exist. And Yuri managed to move on from what her regrets and learn that even though she couldn't help her siblings, it didn't mean that she could blame herself for their deaths.

I apologize for this; I should have stated this earlier. It is implied [read: headcanon] that she knows how to create them due to Chaa having to teach Yuri and the others how to craft weapons (this would be after they first meet, which is prior to the actual creation of the Guild) since the only people who were a part of the SSS during the time were Yuri, Hinata, and Ooyama.

Yes, the samples use the same exact canon point! If an additional sample is needed, however, I have one at the test drive meme post here.