Yale chose to go with Wyba and the beast horde to avoid them having any problems on the way to the designated area for the beast horde.
After all, although they had permission to keep the beasts in Larken City and those beasts were under Wyba's control, it wasn't impossible that someone wanted to kill them due to the fear and Wyba would have a rough time trying to protect the beast horde without harming any of the attackers.
Thus, Yale decided to tag along to use his Origin Sword Bloodline to keep the attackers unable to act towards them; that was the best deterrent for such problem.
Another reason for Yale leaving the group and choosing to go with Wyba was that he had noticed the gaze of Lar towards Aizu and knowing both of them, Yale had no doubt that some conflict would happen among the two girls in a short time. Of course, only a verbal conflict, Yale believed that both of them knew that he would be angry if they provoked real harm to the other.
As for what to do when he knew that a verbal conflict between two girls with romantic feelings for him would happen, Yale had chosen to flee to avoid being dragged into their conflict. He had chosen that option because he believed that if he were dragged into that conflict, no matter how he acted or what he said, the situation would end badly to him.
Yale had read a lot of novels, including some related to romance and the male characters dragged to arguments between two girls with feelings for that character never ended well for the male character no matter how he reacted.
Of course, that was only in novels, and Yale lacked experience in real life, but he still wanted to try avoiding being present in that conflict because he believed that even though a novel might be a bit exaggerated, it shouldn't be that far from reality.
The guess of Yale about that those two girls would have a conflict in a short time was right because those two started a conflict against each other as soon as they were left alone.
Due to Aizu being Yale's disciple, she had a room at the side of the room of Mercer. Lashar felt that it was normal that fellow disciples had the rooms near, to help Yale when he went to teach them. If he needed to go from one point of the mansion to another one each time he wanted to go seeing any of his disciples, it wouldn't be efficient.
Yale's room was near those rooms, but in another area, that area had been reserved for his own use, and no one could enter without his permission. He had done too many cruel experiments in the previous days, so it was normal that Lashar gave so much space to him.
It would have been a problem if she invited someone into the mansion, and they managed to see some of those experiments; experimenting with the souls of others wasn't something rightful after all.
Of course, Lashar didn't dare to tell him to stop using that space after he finished his experiments. After all, the mansion was too big, and she didn't bother by having such space occupied by someone who even the clan founder of the Larken Clan admired.
Until that point, Aizu having a room there didn't have any problem, but Lar's room was the room on the other side of Mercer's room. She had been appointed by Yale to take care of him, so it was normal that her room was also near.
Thus, when Lashar continued her way to show the rooms to the other three, who would reside in another area of the mansion, Lar and Aizu were left alone and then stared at each other.
"So, you are Aizu, Yale's disciple. I am Lar, Yale's fiancée."
Lar wanted to mark her territory showing her status as Yale's fiancée; she hoped that Aizu would just give up.
"Fiancée? So what? I have been a fiancée of two different men due to the orders of my clan, but I never married any of them. In fact, both of them are already dead. Being Yale's fiancée is just something forced by your clan; you can just dream about using that status to suppress me."
Aizu wasn't a little girl who would get scared after hearing about some nobles like she was six years ago; she had matured a lot and didn't fear anyone, especially if that person was her rival in love.
In the past, she had truly thought that Yale would have a better life in the Larken Clan given his talent, but after the years passed, she noticed that she didn't want to give up in her love. Moreover, when Yale showed his prowess, she was sure that Yale didn't need any noble clan as background to turn strong.
Previously, she might have feared that the Larken Clan tried to suppress her, but she already knew the personality of the members of the Larken Clan and they wouldn't dare to act like that. Furthermore, seeing how even the clan leader of the Larken Clan treated Yale with the utmost respect, Aizu doubted that the Larken Clan would put pressure on her even if she competed with Lar for Yale.
After all, she was still Yale's disciple, and knowing Yale's personality, he would be angry if the Larken Clan harmed her in any way. Aizu didn't want to rely upon her status as Yale's disciple, but Lar was relying upon her status as Yale's fiancée, so she didn't have any other option.
Lar was angry at Aizu's bold reply, but she had no way to reply to her because it was just as she had said, an engagement wasn't something that always turned into marriage.
"Anyway, Yale will choose me. Even though I am inferior to him in talent, I am not inferior to anyone else! I am the only woman who can be with Yale. I am the perfect partner for him! On the other hand, you are just his disciple, and your talent isn't extraordinary, you are already lucky for being his disciple."
Lar was trying to destroy Aizu's confidence to make her given up about Yale because she knew very well that being Yale's disciple wasn't something that would provoke difficulties to Aizu to be near Yale and would just make her more dangerous.
"With that body of yours, I doubt that he will choose you. Men like developed women, not women with a child-like body like yours."
Aizu hit on the sore spot of Lar; she was very conscious of the state of her body and seeing how Aizu used that to attack her was something difficult to endure.
"So, what if I look like a child? Yale had allowed me to sleep with him a lot of times!"
Aizu was shocked by that, but she quickly calmed down and replied.
"Oh, so that happened. I bet that Wyba was also sleeping in the same bed."
Seeing Lar's face, Aizu knew that she had guessed correctly.
"Yale is a caring big brother with Wyba, and you also look like a little girl, so I can believe that he decided to treat you as another little sister and thus let you sleep with him."
Lar's face was red from anger because she couldn't negate any of those words; Yale had indeed chosen to treat her like a little sister when he let her sleep with him, but Lar has truly longed him for too much time, so she didn't mind about that.
However, in those days in Sword City, she didn't have a rival like Aizu; at that time, she could just wait patiently until making her body mature to advance in her relationship with Yale, but with Aizu's presence, she felt that she would truly steal Yale if she were to be calm and choose to wait.
"The circumstances don't matter! I slept with him, and you didn't do it, so I have the advantage of position and relationship."
Aizu had to admit that she was a bit jealous of Lar for being Yale's fiancée and having slept with him even being just like a sister. Although those weren't determinant factors, they were still important, and Aizu would want to be considered Yale's fiancée or having the chance to sleep with Yale even if Yale treated her as a sister instead of a woman.
"I have never slept in the same bed as him, but he has carried me like a princess!"
At that moment, Lar was the one feeling jealous because she also wanted to be carried like that by Yale; even in her past life, Liye had never carried her in such way.
Of course, Lar didn't plan to tell anything about her past life to Aizu because Yale didn't want to spread it too much, and she wasn't even sure that saying it would be good for her.
Aizu had proven to have a sharp tongue, and Lar believed that a reason like having had a child in their past lives wouldn't be enough to stop her from countering that reason in some way.