Dax was abandoned as a young child due to an infection, but he accidentally survived.
He became an orphan and was adopted by an aging draconian who treated him as his own.
The adoptive father taught Dax the art of fighting with a long stick and acted as a mentor and father to him as he grew up.
Dax's motivation comes from the sacrifice of his adoptive father, who was killed protecting Dax while resisting a shapeshifter attack on his village, and the protagonist sets out to tackle the shapeshifter in his quest for revenge.