Background
The Down and Out:
XA-86 grew up on one of the few large cities in the outer rim, the son of asteroid miners. He was left an orphan as a kid when his parents were killed because the owner of the corporation cut costs. XA-86 lived on the streets for a bit, but learnt how to survive, spending much of his time in and out of jail for petty theft and vandalism. Eventually, he worked his way into a small black market operation, and from there a anti-Republic group. After getting busted, he leveraged what contacts and money he had to escape off world to a scouting operation in the Unknown Regions.
Motivation
Enemies and Antagonists (Overthrow the Empire)
XA-86 made himself an enemy of the Republic (and thus the Empire), but also made himself some friends. He was putting them at risk by staying away, so chose to distance himself to protect them.