when you can controling Asagi again go to the main hall talk to Whip and Blade then go down and go to the left house, go inside talk to Ura and then move to Police area, walk around until you found the path that go up, go that way until you see merchant it will be some dialogue then come to hall again talk to the green hair where is Whip and Blade had been and it will lead to a battle with Incubus thentake the blue orb and deafeat all strippers in this area to get succubus key and unlock the chest in the left zone of the hall, it's contain an equipment that boost many stat drastically in exchange of speed become 1 and high sexual dmg. Then move down to Police station area find Incubus and beat him to get 1st part of red orb then go to the house in the right (opposite where you found Ura) talk to green man hair. He will turn into Incubus beat him again and take the second part of red orb. after that go inside the cave behind the merchant and put the orb in the crystal each.
Check the crystal what you place red orb is and go into another dimension maze you need to beat boss who guard the area to unlock the way to fight the last boss (IIRC there are Undine, Sylph, Succubus and Angel) after defeat an angel the final warpgate to final boss is unlocked move and face the final boss
Final boss : first part
Beat him with your highest dmg skill or let him win your choice, doesn't matter
Final boss : True Form
Still he is easier than Sadosuto no Do M shit all of his atk are sexual dmg
Most troublesome skill is Fog when he use it you can't deal any dmg to him except Asagi's ultimate skill that can dispel fog and hugely dmg him at the same time and if you ignore the fog he can heal himself more than dmg he recieved from Asagi's ultimate
Also beware sudden defeat skill and make one in our party into defeat state and converted to be his slave and fight your party but you can kill them and convert them back to our side
Converted:
Asagi - High Dmg (the worst situation is Asagi is converted while boss cast fog and our party lack of TP to use high dmg skill
Whip - 2200+ heal to the boss
Ura - High dmg
Bkade - Triple Atk
Keep your TP high and the boss will not hard to be beaten (I beat him by spam normal atk and use ultimate when fogged anyway
