Kouji and Yukihina were opposites in every way; Yukihina was a placid sort, rarely concerned with the value of live and unaffected by the happenings around him. Kouji on the other hand was hot blooded and procellous with a certain respect for life that few power users had possession of. They had not really expected to get along when they first met; their relationship started as rocky at best; Kouji, looking for a place to belong among a world that didn't seem to know him much less understand him, had found his place at Code:Seeker's side. By then Yukihina was already there. To Kouji's knowledge Yukihina had initially joined Code:Seeker with the knowledge that being his ally would give him ample opportunity to plot a thank-you gift of premeditated murder for Masaomi Heike. Somewhere along the way Yukihina had discovered that his ideas were not entirely different form Code:Seeker's and they had begun to get along.
Their personalities were very different and this lead to a great deal of conflict when Kouji first joined Code:Seeker's strange and growing band. Lilly would often laugh at their arguments, thinking that they were, somehow, hilarious. They did not agree and once, without even thinking of it, lashed out at her simultaneously. She avoided them after that.
They were rarely together all the same; though Code:Seeker could not exactly be called a compassionate and understanding man he seemed to understand that it was in everyone's best interests that they did not spend a great deal of time together. That is, until Rui came. A lot of things seemed to change when Rui came; she wasn't like Lilly. She didn't flirt nor was she in any way insecure. She dressed like a man, walked and talked like one. She found her way into Kouji's heart as a comrade quite easily and then, much to everyone's surprise, managed to find a way to melt some of the ice that Yukihina's apathy seemed to be composed of; it's like she doesn't even try.
Rui Hachiouji is the person who brings them together and makes them a family; before they were simply a group of outcasts and outsiders looking for an excuse, almost any excuse, to take revenge on society for the perceived wrongs it had given them. Of course, Rui was not very happy with the way that her life had gone either but that was hardly stopping her from enjoying it. From the moment they arrived wherever they went be it England or Ethiopia, Belgium or Botswana, there were homemade meals. There may not have been a smile when they returned to their hiding place but there was warmth of a sort. Somehow everyone, including Code:Seeker himself, seemed to relax. He may have feared he was growing soft and that was, perhaps, why she was the one he sent to Eden. He could send her away and did, but he couldn't banish the changes she had made. Kouji and Yukihina had found that, rather than being in constant conflict, their personalities could complement each other. They'd gained more members and had become an odd sort of family that none of them had ever expected possible in a group of hell-bent killers.
Though Rui had left she never seemed particularly absent and that was, perhaps, what kept them together when their leader was gone. No one, not even Yukihina, could abandon family.