He is not the only one captured, though. Throughout the series, other individuals are captured and brought to the Village, often to be interrogated or used as pawns in Number Six's attempts to escape.
However, it's important to remember that the Village itself is the primary antagonist in the series. It is the embodiment of control and suppression, and the people within it are primarily tools of its power.
So, while the series has various characters captured, the focus is on Number Six's struggle against the oppressive forces of the Village, rather than individual characters being captured.