I tested this all out on a Aster Knight which has 100% in everything.

Each - or + is 5%. It varies depending on if the puppet class already has above or below 100%. For example, Theatical Star has 125% in AGI, if we use AGI+ to that it becomes 131% and AGI++ becomes 137%. Where as if we take 75% in HP and use HP- it only becomes 71% or if we use HP+ it only becomes 78%. If you use perverted nature on Theatical Star which has 125% in CHM it becomes 250%. So its not 5 flat amount, its 5% of whatever the base number is.

Does that make any sense? I'm not good at putting my thoughts into writing.

Also you may see some natures that you cant pick when making a puppet thats because you get them later on as a book you use use on your puppet which you can buy at the shop, found in a dungeon or are unlocked by a petition a bit later in the game. That being said there might be more that i have not seen yet (post game stuff?).

Originally posted by KzerZa:

Do the natures affect resonance at all? Like do certain natures get on better than with others?

Yes, Some natures get along better with others giving increased rapport but i dont know which ones with which. It would probably require some extensive testing. That being said i dont THINK it can give negitive rapport so only varying amounts of bonus rapport or none.