T'dai was a Jedi Master of the Zabrak species, identified as male, who dedicated himself to the service of both the Jedi Order and the Galactic Republic. His service commenced three centuries following the enactment of the Ruusan Reformations.
Endowed with Force-sensitive abilities, T'dai underwent training within the Jedi Order to master the ways of the Force, ultimately achieving the esteemed rank of Jedi Master. Around 700 BBY, Master T'dai spearheaded a mission, leading a contingent of Knights in a hunt for a group of Bpfasshi Dark Jedi. Among the Knights under his command was his former Padawan, Minch, an alien Jedi belonging to an unidentified species.
During their pursuit, one of the Dark Jedi managed to overcome Minch in combat, prompting T'dai and the other Jedi to step in. Rather than disclose the location of his Master, the Bpfasshi apprentice chose to end his own life. Subsequently, T'dai guided the Jedi in their continued pursuit of the Bpfasshi Master.
Upon the Bpfasshi master's ship's arrival on Dagobah, T'dai specifically cautioned Minch against pursuing him. Ignoring his Master's instructions, Minch tracked down the Dark Jedi Master, confronting him within a cave and ultimately defeating him. However, this confrontation resulted in the dark side leaving a lasting mark on the cave.