A little more detail on how to get from one target to the next.

for the f2p/small spender people, since you won't really directly move from 6/4/4/4 to 7/5/5/5 by just putting all XP into your level 6 to make level seven. Instead you will want to level up your level 4 to level 5 and when you have enough then upgrade a level 6 to level 7. It takes six level 5 to level up one level 6 magatama. Now you can be impatient and immediately level up a level 6 to level 7, but then you have 6 magatama spaces you have to fill by splitting 3 of the other ninjas level 4. Or you can wait until you have nine level 5 before you upgrade.

Before:

ninja 1 = 6/6/6/6/6

ninja 2 = 5/5/5/5/5

ninja 3 = 5/4/4/4/4 or 5/5/5/5/4

ninja 4 = 4/4/4/4/4

After:

ninja 1 = 7/6/6/6/6

ninja 2 = 4/4/4/4/4

ninja 3 = 4/3/3/3/3 or 4/4/4/4/4

ninja 4 = 3/3/3/3/3 or 4/4/4/4/4

Which path you want to take would be up what team you are running and if more power to your ninja 1 is more important than the MUCH larger loss of power for ninja 3 and 4.

Oh, and Ice, this thread isn't in your list of guides.