There is never peace in SAO, even when you just got your new child.
Kirito and Asuna are sure taking their role as parent to heart. I have not been more than a few days and they have already adopted Yui as their child. They have just met this random little girl lost in the wood and they accepted her so quickly that it is nearly terrifying. Usually someone would take some time to consider something like that and it would take some adjusting before their emotion really connect and they really consider themselves parents. Asuna seems to have such a motherly instinct that she straight up jumped on the occasion and decided that yui would become her girl.
In some weird and funny way, they were right. Yui really is their child. Let us look at it this way, Asuna and Kirito were happy together, always smiling. They love each other, but they truly do. They are becoming closer and closer to one another and it is their very love that drew Yui to them. Yui said that she wanted to meet them, she went ahead and found them to become a part of their love, to smile just like they do. She wanted to be their child.
And she succeeded. Asuna and Kirito accepted her as their child and they were absolutely happy with her. They were ready to risk it all to protect her. they were already considering living the rest of their lives with her, to protect her and see her grow. But unfortunately, this never happened.
That Death Reaper was really intense. We see Kirito owning the content everywhere he goes, we are used to it by now, but he was unable to even see that mini-boss level. I doubt that him or Asuna would have made it out of there alive that time if Yui had not intervened with GM power. Yes they lost their precious girl, but at least they are still alive.
Having said that, Holy shit Yui. I knew there was something fishy going on with that girl, but I never expected her to turn into a fiery swordsman, kill death itself and then proceed to disappear telling her parent that she always was but a program to begin with. What a plot twist ! I was expecting her to become Kirito and Asuna legitimate child, never would I have thought she would be gone so fast.
Yet, she is not truely gone, because Kirito managed to salvage pieces of her heart into an in-game item. He plans to remake her when he comes back to the real world, but I have a feeling that coming back to the real world will not be such an easy task. At least I guess that now he does have the motivation to go through with clearing the game, he has found back his reason to live and fight, which should make things interesting for us in the future.
ZeroGhj signing off