Was it Adino or his army that killed eight hundred at one time? 2 Samuel 23:8 KJV
  These be the names of the mighty men whom David had:
  The Tachmonite that sat in the seat, chief among the captains; the
  same was Adino the Eznite: he lift up his spear against eight hundred,
  whom he slew at one time.


I don't understand about warfare in that epoch, but did Adino alone fight and win eight hundred literally or he commanded an army and did that prowess?
Considering that the three generals listed each did fantastic things, it would appear that Andino killed 800 by himself.

For more about the other generals, and the men following them you can read this:

http://www.southernspiritonline.org/inspirational-stories/the-original-band-of-brothers/