No other real player, so one player char and up to three NPC-Chars.
One-man-army probably should be a leverage to the fact, that only player chars get contact with gods and therefore can receive bless and curse. At least this would be my guess.
I just re-start the run around lvl4 to test it out. Manage to hit lvl8 by mass-murdering people in town/shelters. I had to save 1 talent point i got at lvl4 though cause i didnt get a talent point at lvl8. Annnnnd what you said its true.
For those who want to see the difference between with and without One Man Army , i made a bunch of comparison images here:
http://imgur.com/a/27w51>> In short: You get +2 max AP , 6 AP recovery per turn , +70% VIT bonus
( with or without full party )
Thanks for the clarification , so many people made false claims , even those who manage to get the talent yet didnt test it thoroughly . I hope they keep it this way so the balancing can be done easier and less try hards runs anw.