I remember reading this comic as a kid, along with several other of the Valiant comics. They were quite a bit more graphic than Marvel and DC at the time. I hope Sony doesn't tone it down too much for that PG-13 rating. Also, I get why they chose Vin Diesel to play the role, but at the same time... it feels like it is ALWAYS Vin Diesel playing these roles.
Cool concept but feels like I've got the whole story from the trailer...
In the original comic series, his memories (and powers of course) are preserved in his blood. He isn't really a person so much as a body manipulated by sentient nanomachinery. He becomes the first in a line of warriors spanning millennia all born from his blood and the story continues well into 4000 A.D. It would be pretty cool if they actually told the full Blood of Heroes storyline, assuming they have the rights to the Rai comics.
However, they relaunched the Bloodshot comic a few years ago and are now relaunching it again to tie in with the movie, so who knows what it is at this point. Probably just a generic super-soldier with amnesia storyline.