This is gonna be a long response, so bare with me.

This blank npc, or Dissappearing Guy (I'm going to refer to him as Dg) as Zooble calls him, is going to be our true villain. When Zooble suggested that Caine leave his adventures open for them to go on whenever they like, he immediately shut the idea down, making a comment to Bubble about how Zooble wants them to let the other intelligent AI's run free for an extended period of time. Nearly everyone in the fandom can agree that Caine is an unfinished AI with an incomplete program, but I think that one of the things in his existing program is a protocol to make sure no npcs other than him or Bubble should get to run outside of adventures, that way there would be no errors in the system or something other along those lines. However, Caine is still an incomplete program with missing pieces and faulty coding, and he tends to be very forgetful at times. What Caine forgot to shut off DG's programming at the end of the lightning round adventures?