You can only start this Act 8 hours after the completion of Act 17.
Speak with the Cerberus in Protopia (X12, Y20) to begin the act.
Walkthrough
Cerberus will ask you a number of questions. Your responses to his questions will determine whether you will take the Chaos, Neutral or Law routes through the next Acts. The plugin that you receive during Act 19 will also be determined by your answers (Gabriel's plugin for Law answers, Chimera's plugin for Neutral answers & Isis's plugin for Chaos answers). A list of possible answers to get each route is listed below:
Law Answers
Q1: Any special reason with that girl?
A: We're not strangers to each other
Q2: Get out of this situation as soon as possible.
A: Yes
Q3: Don't interfere again.
A: Understood
Q4: Do you think such a feeling only exists for us demons..?
A: Yes
Neutral Answers
Q1: Any special reason with that girl?
A: We're not strangers to each other
Q2: Get out of this situation as soon as possible.
A: Yes
Q3: Don't interfere again.
A: Understood
Q4: Do you think such a feeling only exists for us demons..?
A: No
Chaos Answers
Q1: Any special reason with that girl?
A: There is no reason
Q2: Get out of this situation as soon as possible.
A: No
Q3: Are you ready to fight this battle alone?
A: Yes
Q4: Will you be able to take on the responsibility?
A: No
All Possible Questions & Answers
Q1: Any special reason with that girl?
A1: We're not strangers to each other
A2: I don't really understand it myself
A3: There is no reason
Q2: Get out of this situation as soon as possible.
A1: Yes
A2: No
Q3: Don't interfere again.
A1: Understood
A2: I won't
Q4: Do you think that such feelings only exists for us demons..?
A1: Yes
A2: No
Q5: You're not restricted by anyone?
A1: Yes
A2: No
Q6: Are you ready to fight this battle alone?
A1: Yes
A2: No
Q7: Will you be able to take on the responsibility?
A1: Yes
A2: No
Q8: Do you have friends that will join you?
A1: Yes
A2: No
Note:It is possible to get each route through several other combinations of answers. The examples given are just one possible way to get each.
Go talk with Yamamoto in the Shinjuku Babel Control Room.