The STOUT IFV-FS was a armored fire support vehicle that was in service with Western forces since around 1984. It was part of a family of armored vehicles that also includes the STOUT IFV-SC.
Background and features
Being derived from a lightly-armored infantry fighting vehicle, it possessed a 105mm cannon, which being a tank armament packs quite a punch. It did have less defensive capabilities than a proper main battle tank, however.
The STOUT IFV-FS was in service since at least 1984 with various Western-aligned Private Forces operating in Africa, as well as at least one in service with XOF.
XOF used at least one STOUT IFV-FS during their raid on the Dhekelia SBA Memorial Hospital to assassinate Big Boss in 1984. A STOUT IFV-FS broke through the foyer of the Hospital to engage "The Man on Fire", but was ultimately destroyed.
They would often be seen in various Armored Vehicle Units of various Private Forces operating in Africa when Diamond Dogs operated in Africa in 1984. Diamond Dogs was known to eliminate or capture these types of tanks during this time period.
A STOUT IFV-FS belonging to Zero Risk Security was part of a caravan delivering important materials to SANR/Cipher as payment for their purchase of Walker Gear. However, it as well as the rest of the caravan was halted due to the Armored variant of the Skulls arriving to attack the Diamond Dogs leader, Venom Snake.
Another STOUT IFV-FS, also belonging to ZRS, was also charged with securing the mansion in Lufwa Valley as Snake was rescuing Code Talker, with it being stationed near a bridge while a contingent of ZRS mercenaries arrived to secure the mansion before Snake could escape.
At least one STOUT IFV-FS under the employ of the Contract Forces of Africa were utilized in an armored column during a proxy war against the Soviet-backed MPLA, with Diamond Dogs being charged with neutralizing the armored column, IFVs included.
Behind the scenes
The STOUT IFV-FS appears in Metal Gear Solid V: The Phantom Pain. It has multiple variants, which are more prominent in harder missions. They boast heavier armor, and a more powerful gun, powerful enough to one-shot Snake, even through splash damage. The red variant is the most powerful and sturdy, but the black variants are still just as deadly. The STOUT IFV-FS alongside the M84A MAGLOADER are the only Western vehicles in the game to not have made a prior debut in Metal Gear Solid V: Ground Zeroes.
The STOUT IFV-FS was first seen in one of the earliest preview of Metal Gear Solid V, then known as "Project Ogre", depicting Snake sneaking by one. In the E3 2013 trailer, to showcase the new ability to drive vehicles, Venom Snake was seen commandeering one in Afghanistan. In the final version, however, there are none to be commandeered directly in the field, and they are only encountered during the Hospital Escape and in the Africa portions of the game.
It is roughly based on the M1128 Mobile Gun System, though with a slightly different shaped turret.