Aliens in need of a battlefield chose earth for their war, now in the remnant of the devastating war; a suicidal man must find a reason to save humanity, which is facing extinction.

In defining the protagonist as “suicidal” you’re portraying him as a “least likely” hero. ?Which is a bona fide dramatic gimmick.

Well, wouldn’t casting the protagonist as a “least likely” woman also do the job? ?Make her a liberal arts major, a wannabe poet :-).

Then send her on a “Hero’s Journey” to discover and develop her latent abilities, ?save humanity, save the planet. ? The most likely?candidate for a “Hero’s Journey” is a character whom everyone else in the story thinks is “least likely”.

Whatever, I suggest you develop the plot such that it unravels through a series of movies –a franchise. ?Franchise potential is the honey pot. (And’s is why I give the concept a thumbs up, though it needs polishing.)

fwiw

I think the premise is potentially interesting but the inciting incident needs some work. Like:

What if two alien worlds go to war — and earth gets caught in the crossfire?

Or what if two alien worlds go to war — and one of them invades earth as strategic stepping stone to conquering the other? ( Like in 1914 I, when Germany attacked France by ?invading Belgium –?the “Schlieffen Plan”. ?And again in 1940, as part of the campaign to conquer France.)

Now what plot arise from that inciting incident? I dunno. Humanity’s hope hanging by the thread of one suicidal man seems a stretch. It seems to me that in this story, it is not a character flaw that needs to be spotlighted but a character strength. ?What has he got that ?100’s ?of ?millions of other soldiers doesn’t have that would give him a fighting chance against the superior technology and numbers of the aliens?

(And why not make the earth-savior a woman?)

fwiw