Cabbage Merchant is a character that appears sporadically throughout Book One and Book Two. His character was as additional comic relief. Really who could beat Sokka at his favorite game?
The cabbage merchant was an Earth Kingdom salesman who specialized in you guessed it, selling cabbages. In every appearance his cabbages were destroyed or damaged. The only thing he ever uttered was his catchphrase "My cabbages!"
In Book One, his ill-fated produce products have met their demise by a multitude of characters, first by the Earth kingdom city of Omashu's import control earthbenders, second by Aang and the Omashu mail delivery service (to which he shouts "Off with their heads, one for each head of cabbage!" during their trial), and again by Aang being chased by pirates (where he shouts "This place is worse than Omashu!").
In Book Two, his ill-fated produce products continued by a platypus-bear at the Ba Sing Se ferry boat center and lastly again by Aang within the walls of Ba Sing Se when the zoo animal mass release gets out of control and a rabiroo feasts on his supply (his final speaking part as the rabiroo has lunch is "MY CABB!... Oh forget it." as he throws a head of cabbage over his shoulder exiting the scene). Although he doesn't appear in Book Three, he was a material source for the Ember Island Players where they referred to him as "a surprisingly knowledgeable merchant of cabbage".
In The Legend of Korra, another man named Lau Gan-Lan runs a company named Cabbage Corps which was founded by the Cabbage Merchant.
