Exodus Specialty

From ShinobiWiki

Exodus, an ancient beastly man who was locked up years ago, runs a small shop from the pit to which he is bound in Otogakure. For a couple thousand gold and a few gems (gold and gem amount varies by level), he will teach you his ancient ways. These ancient ways will grant advance your specialty by 1 point (gain 1 chakra and possibly a jutsu in your specialty).

If you choose not to accept his teaching, Exodus may not be too happy unless you count happy as him throwing you out of the pit.