I like the idea of themes. Tuffy's theme color is green. His brother Ruffy's theme color is copper- I decided to make it copper instead of green because I thought it would a bit confusing if they both had green as a theme color, since Ruffy is one of the central characters. Copper is the closest color compliment to green that isn't red. Tuffy's relatives (his brothers, sisters and possibly cousins) are all going to wear a T-shirt or some modified version/variation of it, and garrison belts - square buckle for the males and round buckle for the females. Their shirts or tops are are all going to be green, with Ruffy being they only exception or one of the few exceptions. And their eyes will match the color of their shirts or tops.
I wanted Tuffy's and Ruffy's hair to reflect their namesakes.
I also wanted Tuffy's siblings and cousins to have slang names - either names that start with "T" and end with "Y" or names that rhyme with Tuffy and end with "Y".
Some of Tuffy's friends wear a t-shirt and garrison belt.
Mario and Luigi have a theme:
So do Wario and Waluigi:
and Huey Dewey and Louie:
and the Chipmunks: