Renting and Affinity

I've discovered today that the number of the spirits for rent can decrease even in Great Blessing day. (Previously thought that it happens only in Average Luck and Bad Luck.) I'm being offered 9 spirits from friends and 3 from strangers in a Great Blessing day.


New Conclusion
The strangers you see are:

• The players who have enough affinity (calculated by Destiny Engine using your birthday and their birthdays)
• The players who have similar number of area cleared
• The players who are currently playing the game

The players who have all 3 points will offer a spirits for rent. These players are the same as "friend candidates" under Friends option.