The "Desert Dwellers" are two theives living in an unnamed desert. The taller gal is a nomad named Atacama, the short one is named Sonoran. It is unknown whether Sonoran is a male or a female.
The two travel the desert, in search of any unlucky travelers they might meet, and try to steal what they can. Though, it's mostly Atacama that does the dirty work. Sonoran prefers to stay out of confrontation, and believes that stealing is wrong.
Despite being older, and therefore having much more exposure/expierience in the desert, Atacama is the only one of the two that complains about being hot and sometimes suffers from heat exhaustion, a serious condition. Though, after she passes out, Sonoran seems to always be able to revive her using the cold water that it produces somehow.
Sonoran is actually quite happy to be of assistance, though. and enjoys nursing Atacama back to health on a daily basis. Some rumors say that Sonoran can survive off of sand alone or that it is actually a sentient cactus.
The only way to find out would be to cut it open to see if it had a moist fruity center.

Oh, and also I drew Gendo Ikari for no reason. see him over there on the right?

Idly drawn on scrap paper at work.