Gray Fox (サイボーグ忍者 Saibōgu Ninja, Cyborg Ninja) is a character who has appeared since the original Metal Gear until his death in Metal Gear Solid. In Metal Gear Solid, he is voiced by Greg Eagles. In Metal Gear Solid: The Twin Snakes, he is voiced by Rob Paulsen, who also voices him in Super Smash Bros. Brawl.
 In Super Smash Bros. Brawl
 As an Assist Trophy
Gray Fox makes an appearance in Super Smash Bros. Brawl as an unlockable Assist Trophy in his Cyborg Ninja form. He is unlocked as soon as the player unlocks Solid Snake. His attack involves moving quickly around the stage and swinging his sword, with his swings capable of reflecting projectile attacks. If he falls off a stage, he can come back from the top. He can also teleport from anywhere in the stage and come back from the top. His skill, according to DOJO!, is so great, that it makes a few smashers want him as a playable character.
While Gray Fox as a character first appeared in Metal Gear for the MSX2, Gray Fox in his Cyborg Ninja form first appeared in Metal Gear Solid. In Metal Gear Solid, Gray Fox's main weapon is his sword, which he uses to slice through the Genome Solders and weaken Metal Gear REX that was controlled by Liquid Snake. When Snake and Gray Fox battle each other, Gray Fox initially uses his sword, but later switches to hand-to-hand combat. If Snake tries using any guns against him, he will always use his sword to block the bullets (unless he is "paralyzed" by chaff grenades). In Brawl, Gray Fox uses his sword against his opponents. Gray Fox's projectile-reflecting ability is a possible reference to how he blocks projectile attacks in Metal Gear Solid.
When Gray Fox is summoned in Brawl, he will say either "Make me feel alive again!", "You can't defeat me with a weapon like that.", or "Hand-to-hand. It is the basis of all combat." Whenever Gray Fox is summoned while Snake is on the battlefield (regardless of whether Snake or the opponent summons him), he either says "Like old times, Snake..." or "That's it! I've been waiting for this pain." All of these quotes are some of the things that Gray Fox says in Metal Gear Solid when battling Snake.
A sticker of Gray Fox can be collected.
 Trophy description
An enigmatic soldier with great physical and combat skills. Calling himself "Deepthroat" and equipped with an enhanced environmental camouflage suit, he dedicated his life to fighting Snake. In a twist of fate, Gray Fox ends up protecting his sworn rival from Metal Gear REX. Long ago, Gray Fox fought Snake in Zanzibarland.