Comments/Ratings for a Single Item

Conceive game with third player. His set is not located symmetrical to
other players (e.g., in center of board), and his army is wittingly weak.
He can capture pieces of both sides, and both sides can capture his
pieces.
Will this game be played ok, if this player have no certain goal at all,
but simply think that he must survive as long as possible, and capture as
many pieces as can?
Motivation question is more clear if main players have some purpose to
capture his pieces, like shogi-style drops.
This player also could have some goal, but achieving it should be unlikely
(only if third player plays really good or first two players plays really
bad) - because it's a game of first two players, and the third one is
additional obstacle, and his victory is special outcome, like draw.
Another variant - there are two additional players rather than one, with
equal armies, and their game is independent from game of first two players,
but they obstruct each other for some reason.