From Scratchpad

Unlike other quests, this quest uses real time to determine spawns and times when the quest itself is offered. All times and dates I will be using will be based on Tokyo Standard time.

This quest is given by Sakon, the monk at X21/Y18 of Souhonzan. You must be level twenty-one at the very least, and the quest will only be offered during the weekdays. If you are of the Law alignment, you will be turned away.

This quest is split into five levels, each with its own set of goals and rewards. Check your Quest list to see which level you are. The goals for each level are:

白軍(For Lvl21-30):Fifteen Invader Angels.

黄軍(For Lvl31-40):Fifteen Invader Angels and Ten Invader Archangels.

緑軍(For Lvl41-50):Twenty-Five Invader Archangels.

紅軍(For Lvl51-60):Fifteen Invader Principalities and Ten Invader Virtues.

黒軍(For Lvl61-~~):Ten Invader Archangels, Ten Invader Principalities and five Invader Virtues.

As you may have expected from the titles I used, regular devils cannot be used to fulfill these goals. These special Invader devils only spawn in the Ueno field map on Saturdays and Sundays, at 11AM and 5PM. At these times, the entire field will be filled with these Invaders and they will continue to spawn for one hour. The different devils are scattered across the field, so it may take a while to find what you need.

After you have reached your quota, return to Sakon and you receive a makka reward, a Messian Traest stone, experience and medals. These medals can be traded to Ukon at X21/Y18, who will give you different items.