The Buddy system is a system of AI allies for Venom Snake available in Metal Gear Solid V: The Phantom Pain. Venom Snake can recruit four possible buddies throughout the story, and can have one Buddy accompany him when deploying on a mission. These buddies each have their own equipment, and each have skills that can be developed as Venom Snake grows his bond level with them. A buddy cannot be killed but when their health is low they will automatically be fultoned out to Mother Base.
D-Horse is available after completing the opening prologue, and is used primarily for traversing large distances. He also has other uses, such as distracting enemy vehicles and pooping on the road causing them to slip, letting Venom Snake hang on to the side of him so it just looks like a horse walking. D-Horse has relatively basic skills, and has limited combat use but can be called upon at most times to help escape from a battle. Venom Snake can use any weapons while riding D-Horse.
Most commonly referred to as DD, D-Dog can be recruited as early as the third mission. After encountering him near Shago Village, the Eastern Communications Post, or Wakh Sind Barracks, D-Dog can be fulton recovered and returned to Mother Base. Once the player returns to Mother Base after six missions, D-Dog can be recruited.
D-Dog's primary use is to scout the battlefield and check for points of interest, marking enemies, prisoners, animals, weapons and vehicles. Additionally, he can use various weapons to stun or kill soldiers in a variety of ways, depending on his equipment picked. These things make D-Dog a valuable asset.
Quiet is encountered in the 11th mission, which is begun as Venom Snake makes his way to rescue Huey Emmerich for side op 82 (though Venom Snake can also head to Aabe Shifap Ruins earlier). A sniper battle with Quiet is initiated, and after defeating her, Venom Snake can then decide whether to kill her there, or to take her back to Mother Base. After the 14th mission and the subsequently unlocked side op "Visit Quiet" are completed, Quiet can join Venom Snake as a Buddy.
Quiet is an extremely valuable ally, and her value grows greatly as her bond is improved. She can be assigned to Scout mode to permanently mark enemies and other points of interest, and to Attack mode, in which she will take up a sniper position, and can fire enemies either to cover Venom Snake, or on his command. In a suitable sniping point, Quiet can shoot at any enemy which has discovered Venom Snake. Depending on her weapon, she can lethally or non-lethally take down enemies.
D-Walker is available after completing the 13th mission, and is provided as a gift by Huey. There is no bond with D-Walker, and its abilities are linked solely to its components which Venom Snake develops. D-Walker can be used for combat, for stealth and for search purposes by the player customizing D-Walkers equipment with 3 different loadouts, and is valuable in many situations, though it is slower than D-Horse as a form of transport. Unlike D-Horse or D-Dog, if an enemy spots D-Walker, they will shoot it on sight.
Venom Snake can grow a bond level with each of the Buddies, aside from D-Walker, to learn new skills. Each Buddy has individual ways their bond level can grow, though Venom Snake can grow his bond with all of them using the following methods:
|One of your thrown weapons (magazine, grenade, etc.) hits a Buddy.
|You deal nonlethal damage to a Buddy.
|You deal lethal damage to a Buddy.
|You deal lethal damage to a Buddy with an explosion.
|You take a Buddy with you when you deploy.
|You dismiss or replace a Buddy.
|You inflict fatal damage to a Buddy.
|You exfiltrate a mission with your Buddy in a helicopter (impossible with D-Horse).
|You develop a piece of equipment for a Buddy.
|You stare at a buddy in first-person in the ACC until they respond (once per sortie).
Upon reaching 100% bond level with your buddy (Quiet and D-Walker aside), you can proceed to customize your buddy. For D-Horse, you can customize his fur color, or you can customize his head strip or his feet. Similarly, with D-Dog, you can customize his fur color or his eyepatch to either bare his scar or insert a false eye.
To a certain extent, D-Walker can also be customized, although unlike D-Horse and D-Dog, its customization features are available from the start, largely due to needing to customizing its output. The customization colors are largely the same as with the vehicles and helicopters, in terms of plain colors and camo patterns.