In Power Rangers: Lost Galaxy, the Magna Defender’s human host is Mike Corbett.
The Magna Defender is originally an alien warrior driven by revenge against Scorpius, whose actions led to the death of the Defender’s son, Zika. After the Magna Defender reaches the Terra Venture expedition, his consciousness takes control of Mike Corbett’s body. This possession is why the armored warrior and the human character are closely linked in the story.
Mike is Leo Corbett’s older brother and was originally intended to become the Red Galaxy Ranger. Instead, Leo claims the Quasar Saber and joins the main team. Later, the Magna Defender’s powers are passed to Mike, allowing him to continue as a heroic defender without simply being the original alien warrior.
The main confusion is with Leo Corbett, who is the Red Galaxy Ranger, or with Damon Henderson and Kai Chen, who are members of the core Galaxy Ranger team. Mike’s identity is also distinct from the original Magna Defender’s alien identity, even though the two share a body and legacy for part of the season.