Interesting how Usagi first assumed the turtles were Kappas initially before knowing them. You would think that in a world populated by anthropomorphic animals it wouldn't be so hard to assume that turtle beings existed beforehand. Granted this is more based off of 2003 Usagi, as it seems in 2012 Usagi's dimension only mammals seemed to walk on two legs.
Anyway, this was an idea that came to mind. What if there were Kame Villages, only they were more of a "keep to themselves" type and didn't interact that much to the other clans or towns. And (forgive me if I'm wrong it's been a while,) since there were no Yokai shown in the 2003 cartoon as it was in 2012, the Kappa tales were spawned after early sightings of these Turtle clans.
They are self sustained and don't need to rely on outsiders to get by. This might make them a smidge more rustic to others but there not completely uncultured. Over the years others intruded unto their waters, constantly, and this lead to the various Kame clans to become battle hardened. They fold great big leaves into a bowl to balance on their head, to help assist in training. They favor the art of ninjutsu due to their amphibious nature in utilizing the waters for there attacks. And with their shells and thicker skin they were very hard for the intruders to defeat.
Though over time some travelers did cross into their territories with no intent on threatening them. As more and more people start to hear about them from the "survivers" the more other clans realized their existance as what they were and not what they initially thought of. Even if some now know about them being simply Turtle people, they tend to be secluded enough for others to still think of them as Kappas.
Their villages can be found near any body of fresh water. (Some have claimed to have even spotted Turtle people near the seas as well...)
Due to their natural armor the Kame don't ever think of themselves as indecent at any time. However, due to other's reaction to their apparent "offensive" nature they have implimented cloths. Simple garments made to cover the shoulders and plastron at minimum, held in place with belts as well as the space between their neck and shell. Younger turtle tots don't require clothing unless during special occasions or when traveling. Warriors also don't require to wear anything more than their belts or weapons, seeing as drenched clothing can be somewhat of a hazard in battle. They are almost always seen with their leaf bowls, though -again- this is mainly to keep those who are training fully aware and on their toes.
I know I said this was based on the 2003 TMNT, but I have yet to acomplish on drawing their two-toed style. So this is why the turtles depicted here are drawn more to the 2012 TMNT. Again, very random idea that popped up to me. Yet, I like it overall.
Tmnt belongs to it's rightful owners. I do not own anything.