No other real player, so one player char and up to three NPC-Chars.
In D:OS1 One-man-army made it, so you could get NPCs after taking it, meaning, that you would still had at least those two players chars. In D:OS2 it reads: the scaling bonuses depend on the number of active player chars, so if you are one player and three NPCs you should receive full effect. If you are 2 players with one NPC each, the effect will be lower. If there are 4 players there will probably no effect at all.
Sadly it is not described, how big the difference will be.
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.
