When the Truth Comes Out (TG-Ajin Crossover)

Centuries after Tokyo Ghoul, the war between ghouls and humans is still raging, and the descendants of our lovely (and unlovely) characters from that story are now in the spotlight.
Meet Kei Nagai. He is the descendant of Kaneki Ken, and he is a ghoul. {..Now that I think of it, I'm not sure if he's a half-ghoul or what..} He has been sheltered by his family, locked in their cabin (if I remember correctly). He has no idea he's different from a human like his best friend, Kai, so he gets a rude awakening when his parents are mercilessly murdered and his sister taken. Now Kaito is left to explain the war of ghouls and humans to Kei. How will Kei react to this horrible information? Who was Kei's descendant, and what is in the box that is passed down in his family? How did things really go down for Kei's descendant, and why? Even I don't know, so I hope it's not confusing~!
Disclaimer: I don't own Tokyo Ghoul or Ajin.
Warnings: .. possibly yaoi..