Quote Originally Posted by Yukimura
...so did Erio and Caro (crazy kids and their environment saving).
I can't see Erio being so interested in such things, though hanging around Caro's dragon might have changed him. Caro, however, being a summoner and everything, could be a tree hugger, though. So, my guess is Erio just decided to keep following Caro, waiting for her boobs to grow (he was interested in them right from the beginning, after all). There exist less worthy causes, for sure.