Qwilleran has a very strong attachment to Koko and Yum Yum. Qwilleran is not affected by matters that could threaten his own life, but becomes extremely anxious when matters involve the cats. During the several occasions where they had gone missing, he has risked his own life to save them, and he does not know what he would do without them. He often thinks that his old acquaintances would never believe he could love his cats as he does, and can hardly believe it himself sometimes. There is, however, no question that Qwilleran has an extremely strong bond with his cats.