In The Phantom Pain, players take the role of Big Boss, under the nickname Punished "Venom" Snake, in an open world environment. The gameplay elements were largely unchanged from Ground Zeroes, meaning that players will have to sneak from several points in the game world, avoiding enemy guards, and remaining undetected. Included in Snake's repertoire are binoculars, maps, pistols, assault rifles and explosives. Following one of the series traditions, The Phantom Pain encourages players to progress through the game without killing, using non-lethal weapons such as tranquilizer darts to subdue enemies. Players may traverse the game world with vehicles such as cars and tanks, in addition to traveling on foot or on horseback, and as certain locations are mountainous, players can opt to scale a rock face as a short cut. They may also call for friendly helicopter support against enemy soldiers in a combat alert or send commandos to scout a target area. Snake can also call on AI companions—including Quiet, a silent female sniper with supernatural abilities; D-Horse, a horse with a customizable saddle for carrying more equipment in the field; D-Walker, a manned, highly agile mobile weapons platform that can provide heavy weapons support; and D-Dog, a wolf pup raised and trained on the new Mother Base to assist him in the field. The companions' abilities and their effectiveness will depend on the player's relationship with them..