I remember this song being first played during season 2 of Mighty morphin power rangers, although i could be wrong on that point. I'm listening to the song for this next part. The "We" In "We Need A Hero" would be us. The "Hero" in the lyrics would be the power rangers. They also refer to "the one who will lead us" probably refering to the red ranger. They refer to "There will be hell, waiting for them to find us" The them there, would again refer to the team of rangers. So as the verses are going I'd have to say It's refering to 1. The Rangers. 2. the leader of the rangers (Red, or in season 2 when tommy lead the team; white) 3. We, as a people.