So, I'm playing around with designing a tiny creature, and I thought about using the Swarming trait of Ratfolk fame for them because it seemed to fit the style of creature I'm creating.
To wit:
Swarming (1 or 2 RP): Prerequisite: Medium or smaller size; Benefit: Members of this race are used to living and fighting communally with other members of their race. Up to two members of this race can share the same square at the same time. If two members of this race that are occupying the same square attack the same foe, they are considered to be flanking that foe as if they were in two opposite squares. Special: If the race is Small or smaller, this trait costs 1 RP. If the race is Medium, it costs 2 RP.
However, I'm not sure it will actually do anything, at least as written. So questions for my more rules knowledgeable colleagues out there:
1) Tiny creatures can fit up to 4 members in one space. The Swarming rule doesn't really seem to have been written for creatures other than Medium or Small creatures. Should more creatures of smaller size with the Swarming trait be allowed in a square? Or does the added benefit of being able to flank with another member balance things out?
2) As Tiny (and smaller) creatures have no reach and must be in the same square as another creature to attack it, will this trait even be of any benefit to them at all? Should multiple smaller than Small foes be allowed to enter a square with another creature (see above)?
Correct in that Swarming has no use for Tiny creatures without additional rules being added. Now, if you had a tiny creature with a 5' reach (say, with a tiny polearm, which I think would work), then two or more in one square would be able to use the Swarming trait to flank the target, but otherwise I think it is unnecessary.