Hostage

Hostages are people who are held prisoner by a foreign party. Although technically similar to a prisoner of war, a hostage generally indicates someone abducted and held against their will by an enemy (usually a terrorist group), usually to dissuade another party from doing a particular action against them, and in certain cases force a particular party (usually those the hostage knows well) to do their bidding.

The Philosophers
Shortly after Ocelot's birth, the Philosophers abducted him, and later indirectly threatened Ocelot's life to his mom and dad, the Cobra Unit members The Boss and The Sorrow, respectively, in order to force them to fight to the death in Dolinovodno, Tselinoyarsk to save their son. The Sorrow then gave his life to ensure Ocelot and The Boss survived. This had occurred after a culmination of various factors, in particular The Boss using the Philosophers' channels to put in a sleeper agent into the Soviet Union.

Outer Heaven
Although the prisoners in Outer Heaven were technically POWs, three of the prisoners, including Jennifer's brother, were held hostage by the Outer Heaven mercenary Dirty Duck during his fight with Solid Snake in an attempt to dissuade Snake from trying to kill him.

Sons of Big Boss
During the Shadow Moses Incident in 2005, the Sons of Big Boss terrorist group composed of both the FOXHOUND members as well as the Next Generation Special Forces took hostages among the staff, including DARPA Chief Donald Anderson and ArmsTech president Kenneth Baker, and to a lesser extent Otacon and Meryl Silverburgh, Metal Gear REX's engineer and a former FOXHOUND recruit, respectively. Only Otacon and Meryl survived, as Donald Anderson was killed by Ocelot in a manner that looked like an accident during the interrogation against him and then replaced by Decoy Octopus, and Kenneth Baker was killed via the FOXDIE virus to silence him about Metal Gear REX's development.

The Patriots
During the Shadow Moses Incident, although not directly taking her hostage, the Pentagon, or rather, the Patriots, was implied to have deliberately allowed for Meryl to be transferred to Shadow Moses Island the very same day the revolt happened and then taken hostage by FOXHOUND in order to force her uncle/biological father, Colonel Roy Campbell, into doing their wishes during the operation, including hiding key details about REX's development, the true nature of Shadow Moses, and FOXDIE. In addition, the Patriots via Richard Ames also had Nastasha Romanenko forced to work with the mission support.

The Patriots later abducted Olga Gurlukovich's child shortly after her birth and ordered for her to aid the FOXHOUND "operative" Raiden as the Cyborg Ninja for the purposes of their S3 Plan, even if it meant killing her own men and her death. They later pulled something similar to Raiden late in the operation by holding the real Rosemary hostage, as well as indicating that they'll kill her (and their unborn child) alongside Sunny if Raiden doesn't fight Solidus to the death and kill him. They were also indirectly responsible for the Sons of Liberty holding hostages during the Big Shell Incident.

Gurlukovich Mercenaries
During the Gurlukovich Mercenaries' takeover of the USS Discovery (tanker) in 2007, the Gurlukovich Mercenaries held the marines within the Metal Gear RAY holding area hostage, with their leader, Sergei Gurlukovich, personally holding Marine Commandant Scott Dolph hostage. However, this ended in disaster when both Marines and various members of the Gurlukovich Mercenaries were wiped out by a treacherous Revolver Ocelot.

Sons of Liberty
The Sons of Liberty terrorist group during the Big Shell Incident in 2009 took various hostages, which included a woman named Jennifer, supposed Secret Service member (and secret Patriot and DIA agent) Richard Ames, Emma Emmerich, and President of the United States James Johnson. Ames, however, was implied to have secretly infiltrated the hostages in order to relay orders to Raiden and possibly take out James Johnson for siding with Solidus. Johnson wasn't initially a hostage, although he soon became one upon learning he and Solidus had different aims for Arsenal Gear. The Patriots via the Colonel also claimed that the Sons of Liberty killed one of the hostages, although they never actually did this. Ames ended up dying due to his pacemaker being remotely deactivated by the Patriots in order to simulate FOXDIE, while Johnson was killed by Ocelot shooting him in the back, and Emma was killed by Vamp stabbing her in the abdomen when put in a human shield position. Several of the hostages were also injured from stray gunfire when the Cyborg Ninja arrived and attacked several of them, with some being left to die due to their not being enough room on the Big Shell.

Desperado Enforcement LLC
The Desperado scientist in Mexico took George hostage in an attempt to force Raiden to not save the children that were being gassed in a nearby room, although this resulted in his death when Raiden, at George's encouragement, cut both of them down.