I'd have to nominate two complimentary NPCs; Captain Price and Gaz. Seriously though, I'd like to know what happened in Beirut and why Kamarov owes them one. Gaz was an awesome sarky character and they shouldn't have made a sequel without him (Gaz >> Ghost by a factor of OVER 9000!), but there was plenty of room for a good prequel methinks; we can hope for a better game, but we're not going to get it.
If that's not allowed, then I'd have to go for Strider from Stalker: Call of Pripyat; I think he could have an interesting tale about him.
If that's not allowed, then I'd have to go for Strider from Stalker: Call of Pripyat; I think he could have an interesting tale about him.