I was recently stuck but I managed to find a way out of this part.
 

Return to the Start Of The Area

After passing the first miniboss, (, and the old man), return to the beginning of your dungeon.
 
 

 
 
Wait for a Demon to spawn (. Not the enemy demon).
 
 

 
 
This dialogue should take place

 
 

 
 
Here we come to an end for Soul Hackers 2 Central Line Key Location hope you enjoy it. If you think we forget something to include or we should make an update to the post let us know via comment, and we will fix it asap! Thanks and have a great day!