Several times during the fourth season of Battlestar Galactica (2004), Starbuck is referred to as the harbinger of death (for instance, at the ending of Razor). But if anything she ends up saving everybody by leading them to the new Earth.
So what was that herald of the apocalypse stuff about?
This is what I thought, because I am a expert in plot twist and I thought they meant death or the end of something else but the beginning of something else as well.
The "Harbinger of Death" Explained
Kara does not lead the human race to its end as one would initially think. It seems that by "end" the hybrid meant not their destruction but their goal, seeing as she actually leads Humanity to a new home and saves them from extinction.
However, since all of today's humans are distant descendants of Hera Agathon, the "pure" human race did in fact come to an end over the generations that followed. Furthermore, by abandoning its advanced technology and making peace with the Cylons, Colonial Humanity came to an end and started over from scratch as Earth Humanity.
Kara being the "harbinger of death" can also be explained as her having died and then being brought back to life. Thus, she is "living proof" of the notion that everything dies and that there is life after death. This is evidenced by her role in the events leading up to the destruction of the Cylon Hub.
It is not entirely clear why the First Hybrid did not want the human race to follow Kara. One possibility is that he did not want humans and Cylons breeding together. Another possibility is that he wanted the Cycle of violence to continue for some reason. It is also not clear why Kendra Shaw was given this warning only to have her message to Pegasus jammed.
She was sort of the herald of the apocalypse because her leading everyone to the end did bring about a lot of death. Also, didn't she put the last coordinates in that ended the long journey.
I think people were expecting to much death and that is why they were surprised when it wasn't a full on apocalypse with everyone dead.
A deleted scene included in the extended DVD cut shows Starbuck and Helo getting drunk at Joe's Bar, and Starbuck ruminating on her destiny as the Harbinger of Death. She says finding nuked Earth pretty much fulfilled that part of the plan and she wonders what her purpose is now.
Helo suggests other meanings for Harbinger, such as herald, to suggest her destiny could be positive. This scene foreshadows Starbuck's use of the music to find the second Earth in "Daybreak," and implies her role in leading the human race to its end refers to finding the planet where human and Cylon can live a blended existence.
Also there is a picture you can observe from this link.
From this picture a lot of people died, due to the harbinger of death who saved and condemned loads of people.
So another possibility of why the First hybrid said "they must not follow her," meaning Kara, could be that had the entire colonial fleet followed her, Kara would not have been able to make peace with the rebel Cylons. Think of this, if the Galactica had been there, with the entire fleet, they may have destroyed the Rebel Baseship. Since it was only Starbucks and the Demetrius, a fight was avoided and thus Kara was able to forge an alliance and help bring that to the fleet and their search for Earth. In this aspect the wording of the warning to Shaw makes sense. Even though the First Hybrid is much more coherent than the modern hybrids, much of what is said is still vague and doesn't really make sense until after we see what happens.
Harbinger Of Death is the supernatural power to sense an impending death or a death that has already happened. Right before she disappeared she had an epiphany and realized she was a messenger or Angel of the dead Kara Thrace. She at that moment became the harbinger of death. When Apollo looked around he also realized Kara was dead. Sam also realized it, his last words to her before flying into the Sun was "I'll see you on the other side." In the book series Lords of Kobol you realize the second Starbuck was a messenger sent to lead them back to earth. She got so upset as they jumped away because with each jump she was becoming confused and her missions purpose was being erased. She was "forgetting" She came to the point where she thought she was the original version of self. When she discovered her dead body she became lost and psychologically disconnected.
I didn’t think of Kara destroying the Resurrection ship, and it’s true that she brought humanity to its conclusion. If you think about it, humanity (of the Galactica ship) would be interbreeding with early man (as Apollo said), but also the human Cylons (Hera wouldn’t be the only child of human with Cylons).
So technically, Starbuck brought brought all three groups to an end, while creating a new form of life by mixing them together. Now, if only the metal head Cylons wouldn’t find another group of people to conquer on a different planet, everything would be great.
Actually Starbucks is the harbinger of death because she leads them to destroy the Resurrection Hub, essentially making all Cylons mortal.
Technically, she did bring them to their end. Remember when they flash forward to the future? The oldest human was Hera. All of the humans we are descended from a human/cylon hybrid. Pure humans went away. When Starbuck led them to the new "Earth," humans as they knew it were led to their destiny. Their race was eventually replaced by a cylon/human hybrid and the "humans" that already existed here. The colonial humans ended.
