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 Hiiragi, the Temple Knight at X21/Y28 of Arcadia. 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 Chaos 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:

Lvl 1(For Lvl21-30):Fifteen Invader Blobs.

Lvl 2(For Lvl31-40):Ten each of Invader Tarakas, Invade Karasu-Tengus, and Invader Onis.

Lvl 3(For Lvl41-50):Five Invader Blobs and fifteen Invader Gorgons.

Lvl 4(For Lvl51-60):Ten Invader Gorgons and five Invader Nizzhogs.

Lvl 5(For Lvl61-~~):Fifteen Invader Nizzhogs.

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 Shinagawa 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 Hiiragi and you receive a makka reward, a Gaian Traest stone, experience and medals. These medals can be traded to Temple Knight Sakaki at X23/Y20, who will give you different items.