Amadeus is the leader of the Amadeus Syndicate, and the primary antagonist of Metal Slug 4, where he serves as the game's final boss.


Metal Slug 4

As the head of the Amadeus Syndicate, he helps Morden to obtain new weaponry and also creating his own army. He is the final boss of Metal Slug 4. He controls the Amadeus Mother Computer, a three part contraption. After defeating him, the base begins to collapse while he is still stuck inside the last machine. It is unknown if he survived the destruction of the base.

Metal Slug Attack

Amadeus appears several times in Metal Slug Attack, both in Extra Ops and Another Story. Just like in Metal Slug 4, he is affiliates with Morden and his army. Amadeus is referred to as the Doctor, both by the characters and in-game.

In "Amadeus' Revenge" Extra Ops, he tests out a new Type γ Mother Computer and is delighted with the results. When confronted by the clumsy Rumi, he attempts to kill her with lasers, but she dodges them. She then throws grenades which seemingly miss, causing him to laugh. The grenades suddenly reappear again and explode, destroying the Mother Computer, though he survives, and is clearly not pleased.

He appears in Another Story in the chapter "Guilty Child", where Amadeus soldiers bring Abigail to him. When Abigail warns him to speak carefully, he is confused with what is happening. Amadeus recognizes Allen and remarks about how he's grown, resulting in Allen wondering if Amadeus is getting senile. Allen then tells him that his robots attacked them on the way to the headquarters, and he takes out a holographic keyboard, showing them he controls the robots. He stops when Abigail asks him why he created robotic versions of Morden with a little girl's voice. Amadeus tries to stop White Baby from causing more havoc, but is helpless as he is forced into a Mother Computer to battle the two.

After the battle, he tries to stop White Baby from leaving but is unable to. He apologizes to the rebel officers for causing unnecessary trouble and explains White Baby to them. He offers to help them by finding White Baby before it can cause more trouble. When Abigail tells him that they will destroy her, he silently agrees, something which Allen interprets as a parent worrying for their child.


Although Amadeus' personality is never shown during the main game, In Metal Slug 4, he unleashes a sinister, maniacal laugh upon seeing the player.

In Metal Slug Attack, he is shown as a caring figure. Not having any children of his own, he created various AIs to mimic them, as shown with White Baby and Iron Fortress as both are AI appearing as children, and has grown attached to them as a father figure.


  • Amadeus reuses the sprite of Parker, the businessman/representative of a video game company who had his briefcase stolen by the player in Metal Slug 2/X.
  • Amadeus and Invader Queen are only final bosses which have their own final boss theme.
  • Amadeus has unused sprites of himself walking and smoking a cigar.


Heroes Marco Rossi | Tarma Roving | Eri Kasamoto | Fio Germi | Trevor Spacey | Nadia Cassel | Ralf Jones | Clark Still | Leona Heidern | Walter Ryan | Tyra Elson | Roberto Nicola | Nathalie Neo | Alisa Stewart | Hero | Gimlet | Red Eye | Tequilla | Amir
Support Hyakutaro | Rumi Aikawa | Madoka Aikawa | Utan | Navel | Issenman Tarou | Eris
Villains Donald Morden | Allen O'Neil | Abul Abbas | Rootmars | Amadeus | Evil Spirit Incarnate | Ptolemaios | Invader Queen | Allen Jr. | Oguma | Macba | Lt. Wired | Kanan | Hilde Garn | Unknown Alien
Instructors Sophia | Margaret | Lilly | Mary | Cynthia
NPC POWs | Parker | Satiko Suzuki | Gerhardt City Civilians | Scott Amundsen Jr. | Miner | Genie of Lamp | Orca | President | Sailor | Chinese Soldier
Cameos KOF Team | Battle Cats
Unused Achilles | Tabomba | Ptolemaios
MSA Newcomers Scotia Amundsen | Pharaoh | Red Goblin | El Dorado | Professor | Dragunov | MS-Alice | Abigail | Vatn | Yoshino | Odette | Beatriz | Caroline | Cleopatra | Vita | White Baby | Annette | Lydia | Anna Wiese | Jin | Veronica | Navy | Percier | Aileen | Nova | Elysion | Sisilia | Esther | Aswang | Destrade | Midori | Nowan | Shizuka | Rapid | Towa | Huracan | Aisha | Mira | Elena | Licht | Simon | Julia | Anastasia IV | Mello | Schwarz Metzelei | Chloe | Miharu | Izabella | Rita | Amber | Agalia | Ariadna | Perche | Nikita | Chunyan | Reika | Fedeln Metzelei | Grazia | Alma | Owen | Iron Fortress | Rillacle | Loretta | Ichima | Ami | Gemini Twins | Edda | Sho | Halle | HMT | Arsinoe | Molly | Dion | First Baby | M.D.P.S-Mz 3 | Norah | Maria | Franke
Metal Slug Tetsuyuki | Hairbuster Riberts | Tani Oh | Shoe & Karn | Iron Nokana | Hi-Do

Mini-Bata | Allen O'Neil

Metal Slug 2/X The Keesi II / Iron Nokana MK II (X) | Aeshi Nero | Dragon Nosuke | Big Shiee | Hozmi | Rugname

Mosque Artillery | The Keesi II (X) | Allen O'Neil | Dai-Manji

Metal Slug 3 Huge Hermit | The Ten Commandments of Moses | Jupiter King | Sol Dae Rokker | Rootmars

Twin Ohumein-Conga | Monoeyes | Hairbuster Riberts | Hi-Do | Rugname

Metal Slug 4 Brave Guerrier | Toschka Dalanue | The Iron | Big John | Sea Satan | Amadeus Mother Computer

Mecha Allen O'Neil

Metal Slug 5 Metal Rear | Shooting Ray | Wall Crawler | Sandmarine | Evil Spirit Incarnate

Black Hound | Stone Turtle (unused) | Mammoth Tower | Ptolemaios (unused)

Metal Slug 6 Bull Drill | Iron Sentinel | Brain Robot | Sea Worm | Invader Queen

Invader Controller

Metal Slug 7/XX Worm Mecha | Crablops | Destroyed Crablops | Fall Mecha | The Union | Rebel Gigant | Kraken
Metal Slug: 1st Mission Rebel VTOL | Rebel Train | Macba | Rebel Zeppelin | Electromagnetic Crane | Weapons Port Boss | Hilde Garn

Facility Elevator | Macba | Rebel Truck

Metal Slug: 2nd Mission Big Bertha | Terrain Carrier | Rebel Reactor | Macba | Rebel Submarine | Tani Oh | Gunslinger | Rebel Submarine | Rebel Airplane | Hilde Garn's Slug | Rocket UFO

Rebel Rocket | Hyakutaro

Metal Slug Advance Formor | Emain Macha | Kaladgolg | The Keesi III | Cabracan

Allen Jr.

Metal Slug 3D M-3 Rocket Van | Mosque Artillery | Spider-Bot | Rebel Underground Drill | Morden Battleship | Morden Castle | Allen O'Neil | Lugus | Lieu Monster
Mobile games Rocket Control Room | Unknown Alien | Hellfire | Spiderbot | Cyclops | Mega Laser Turret | Mars Battle UFO | M-32 Water Carrier Plane | Mecha Kaiju | Alien Floating Structure