The Chosen Ones

End chapter and don't avoid (don't press Esc) the final interlude of Ch 8, then answer the riddle questions and another time don't press Esc or load screen to ch9 will appear. Do a Pick fast of Phodom and try to dig. Then the lights will turn on, and you can control all characters.
To Aero, don't worry anything will be wrong to ch 9, you can't benefit from any item, gold, combat king, alchemy, or another abuse, because the chapter is closed when you pressed End this chapter, and nothing will be load after that.