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

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

This is an odd story, you have a suicidal man who 'must find a reason' to save humanity.

This suggests that the lead character has the ability to save humanity ?but isn't sure if he should. So the story would be about the inner conflict of the suicidal man deciding whether he should save mankind or not. Sort of 'to be or not to be'