Mezlo was a strategist, a male human hailing from the planet of Oru. Following the First Order's conquest of Oru, he spearheaded an Oruan warrior based resistance group to try and liberate their world. Their efforts were unsuccessful, compelling the Oruans to flee and ultimately settle at Horizon Base. Finn and Gannis Ducain, both from the Resistance, visited Horizon Base with the intention of enlisting the Oruans, though they were met with initial reluctance. Mezlo ultimately changed his mind, pledging to support the Resistance upon request, though choosing to remain behind.