Masago, a female human Sith Lord from an unnamed planet's royal family, concealed her allegiance while plotting her brother the king's murder to seize power. Her appearance featured blonde hair, red eyes darkened by the Force, and a muscular build with broad shoulders projecting physical dominance. As ruler, she banished her niece Princess Misa and fortified the palace with security checkpoints. Masago wielded a belief in predetermination as a manipulative tool, invoking destiny to sway adversaries to her cause, mirroring classic Sith recruitment.

When Princess Misa allied with Jedi Knight Tsubaki—her father’s former protector—to challenge Masago, the Sith Lord dueled Tsubaki at the palace. She taunted his perceived weakness in combat while promising to unlock his true potential through the dark side. Her psychological assault intensified after Tsubaki accidentally struck down Misa. Masago issued an ultimatum: become her apprentice or let Misa die. She argued that only by gaining power as her right hand could he protect the planet and save Misa. Tsubaki accepted. Together, they performed Force healing to revive Misa, after which Masago departed the planet with her new apprentice.

Her tactics fused combat prowess with exploiting emotional vulnerabilities. Skilled in lightsaber dueling, she also induced dark side visions and demonstrated rare mastery of Force healing—typically a light side ability—underscoring her comprehensive command of the Force. Masago’s methodology consistently leveraged others' attachments, exemplified by Tsubaki’s corruption.