Ralf Jones is one of the playable characters since Metal Slug 6.
"OK, Let's get this done!!!" - Ralf's pet phrase
Though he is a colonel of his mercenary squad, his background is a complete mystery. Rumor has it that he came from a certain nation's special forces, or that he eradicated some secret society; Ralf shows no interest in such rumors. He does seem quite close to his commander, but no one has any clue as to how they met. He and Clark are brothers-in-arms, and they always go to battle together. He is known to participate in tournament fighting, and his close quarters combat ability far outstrips the average fighter. He is well known for his Vulcan Punch, a powerful salvo of punches powerful enough to kill infantry and destroy tanks. His most prized thing is a medal given to him by the president.
In Metal Slug 6 and Metal Slug 7, Ralf is most skilled with the melee attacks. Not only can his melee attacks cause double damage, he can also use his Vulcan Punch that can destroy even enemy tanks. Ralf is also able to withstand two shots instead of just one like the others (although they can get up if they landed on a special weapon upon receiving a standard ranged death). Ralf however can only carry half the ammunition for special weapons.
- Both Ralf and Clark originally appeared in the Ikari Warriors series. In the U.S. and European versions of Ikari Warriors, they were renamed Paul and Vince, respectively. They both also appeared in the The King of Fighters game series, under their original names.
- Ralf's sprites are actually edited from Marco's.
- In the game Universal Metal Slug: Fierce Battle, Ralf can be killed in 1 hit, using Marco's death scream when killed.
- He was named as Ralph Jones in Universal Metal Slug: Fierce Battle.
- In Metal Slug Defense, he uses his other special punch, the Galactic Phantom, a ramming single punch that bursts anything on flames upon contact; a punch which he uses mainly for his former tournament fights.
- In-game, Ralf can easily destroy any enemy vehicles with ease.
- In Metal Slug Attack, he's first available as a demonstration unit for the game's tutorial, however, similar to a campaign with Leona which required medal purchase of 10K, Ralf was a pre-acqisition unit, and was available in the Medal/VIP crank, and can now be available to purchase from the POW Rescue Shop. He also appears there as a placement image for the VIP crank. Once his skill levels are Maxed out, his Galactic(a) Phantom special can also produce another ability, once the GP is performed, 4 fireballs similar to Dragon Nosuke, Jupiter King, and Metal Rear's attacks will appear in the air and damage enemy units further.
- He also has an alternative version called Crazy Ralf, which is just a reskinned red Ralf with Galactica Phantom as his long range move and his dive punch as his special move. Just like in Metal Slug 6 and 7/XX, he can revive once, if you max out his skills. Unfortunately, his illustration (KOF XII/XIII version) doesn't match his sprite however, hence the confusion.