Mattis Banz was a Force-sensitive human male who was a member of J-Squadron, a training group within the Resistance against the First Order. Born on the farming planet of Durkteel in 20 ABY, Banz grew up as an orphan, residing under the care of a Phirmist temple, where he heard tales of the Rebellion that overthrew the Galactic Empire. During this time, he developed a heroic personality, dreaming of becoming like Luke Skywalker, Leia Organa, or Admiral Gial Ackbar, and he often helped younger orphans in need.
In 34 ABY, Banz's actions were noticed by Resistance recruiter Antha Mont, and the orphan joined the Resistance, training to become a pilot in a group of cadets known as J-Squadron. A month after arriving at the Resistance base on D'Qar, Banz and a few other members of J-Squadron caused an accident which could have resulted in the deaths of several starfighter pilots. As a punishment, Admiral Ackbar sent them on a scavenging mission to Vodran. However, while on Vodran, Banz and the group encountered stormtroopers of the First Order and were taken captive.