Theoryland of the Wheel of Time

Kwaan went into hiding, and he was eventually discovered and executed by Rashek. He wasn't among the First Generation, though he would have been if he hadn't turned against Rashek. Rashek kept the plate, however, just as he kept Alendi's logbook. Partially because even then, Rashek was going a little mad, but partially because of the reminders about his old life they contained.

VEGASDEV (17 OCTOBER)

I'm assuming you meant Alendi hunted him down because he turned against Alendi. Or did Kwaan also turn against Rashek?

BRANDON SANDERSON

No, I meant that he turned against Rashek. Remember, the members of the First Generation were offered immortality in exchange for their Hemalurgy. They had to make this choice for all of the world's Feruchemists. Because his uncle had been the one who gave Rashek the chance to become the Lord Ruler in the first place, Rashek blessed him and included him in the decision. (Speaking directly into his mind along with the others during Rashek's moment of ascension.)

Kwaan was the only one who turned down this offer, calling it a betrayal of who they were as a people. Rashek could have just made him one anyway, but in a moment of anger, he tried to destroy Kwaan—which he couldn't do, not with Preservation's power. As the other Feruchemists changed, Kwaan remained the same. Rashek eventually hunted him down and killed him.