Short answers, pulled from the story.
Konami officially unveiled Ground Zeroes on the 30th of August 2012 during a private function celebrating twenty-five years of the franchise. Hideo Kojima revealed very little detail about the project at that time other than it would be a prologue to Metal Gear Solid V.
The game features AI companions including D-Horse, a horse capable of hiding Snake during travel, and D-Dog, a wolf pup raised to assist in field operations. Quiet serves as a mute female sniper with supernatural abilities while D-Walker acts as a manned mobile weapons platform providing heavy fire support.
In 1984 nine years after Militaires Sans Frontières destruction Big Boss awakens from a coma inside a hospital on a British military base in Cyprus. A Cipher assassin named Quiet attempts to kill him but fails when a heavily bandaged man called Ishmael rescues them before they escape while evading pursuit from Cipher soldiers and two superhumans known as the Third Child and the Man on Fire.
Before the game released in 2015 presentation of female character Quiet became a major controversy topic regarding her appearance and oversexualization. Halo content producer David Ellis criticized her for reinforcing stereotypes about the industry being full of man babies while Western audiences criticized the figure's soft pliable breasts drawn by Kojima and Konami in May 2015.
Metal Gear Solid V shipped three million physical copies within first five days across all platforms. On release date game grossed US$179 million higher than combined opening day box office of Avengers Age of Ultron and Jurassic World films.