Campaign of Evil
Drax does not remember much before he was captured. He cannot recall wether his scales were always this rusted red color they resemble now. Somewhere deep within him he feels that once he might have been a prismatic gold. Now his skin is covered in scars and his soul is filled with hate.
Drax was captured young, simply for his unusual look. Dragon born are rare, and could always bring in a crowd. The slavers knew this. At first he just stood there, bound in chains while the audiences oohed and aahed. Eventually Drax grew large and the slavers forced him to fight. His refusal was only met by torture, so he fought. The pit-fight/arena style matches were brutal, often to the death. But Drax prevailed, either through raw strength or because the slavers would never let the main attraction die.
Over time Drax became battle-hardened. Disallowed by his captors to wear armor, (this would hide his unusual appearance), his scaly skin is covered in scars and cuts which make him shocking to see, and quite intimidating. He finds that most folk steer clear of him and will look down as he passes. He is large and wields a two handed mace he looted from a large fighter after setting him on fire and watching him burn.
One high-elf named Loaky would often come to these fights, betting on Drax and most often winning. Drax paid him no attention until one night Loaky awoke the dragonborn from his slumber and helped him escape his bonds. Loaky was running and was taking Drax with him. They left the slaver camp together, burning it to the ground behind them. Wether it was just for protection or out of kindness, Drax did not know. Now, though, they have a bond of friendship and Drax will escort Loaky through anything and will guard him with his life.