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Iron
Sentinel

This page relates to a Metal Slug Attack unit; for information about this boss in the main series, see Iron Sentinel.

MSAUnitSilver
MSAUnit Iron Sentinel
Iron Sentinel
Rarity
MSA rarity Super Rare
Faction
MSD faction Rebel Army 24px Rebel Army
AP cost
MSA dot III 900
MSA dot IV 810
MSA dot V 720
Optimal range
Long
Traits
Critical
Second Form
Playable since
1.8.0
In-Game Description
"This ultra-giant size missile tank was created in cooperation with Mars People. Gen. Morden himself is aboard."
Iron Sentinel MSA idle

The Iron Sentinel a playable unit in Metal Slug Attack. It is one of the most difficult units to unlock, as parts are only available for purchase via the Mars Shop.

As Mars Currency can only be obtained by trading in platinum evolved units, it's generally easiest to obtain it by gathering Rare unit parts from the MSP crank. Once all the crank units have been fully evolved, every additional ~2.43 million MSP spent on 10x pulls will average enough Mars Points for a Sentinel part - and so a platinum Sentinel (or Rootmars Slug) can be obtained for about 800 million MSP (minus however many additional points are earned from events and other cranks).

The Sentinel itself is a very large multi-treaded tank that shoots missiles and projectiles from its ball turret. If MSA Skill small + 4 is unlocked, when first destroyed, it will switch to a secondary form that shoots even larger missiles with a wide area of effect and a higher damage output.

It has fairly high health for a backline unit, and its large size and long range missiles makes it a formidable foe to fight, especially when buffed. The 2.13.0 update doubled its base health and long range damage, increased its special damage by 20% per shot, and additionally had its special fire extra shots.

Attacks

Long Range

Attribute grenade Missile (Spread) - Launches a salvo of missiles from its side. If in second form, shoots out very large missiles.

Special

Attribute grenade Big Missile (Spread) - Fires larger missiles from its main turret, and bombs from its side.

Stats

Health Attribute Resistance
Lvl MSA dot I MSA dot II MSA dot III MSA dot IV MSA dot V Attribute pistol
Kinetic
MSA resistance 1-Increased Increased
1 40000 44000 48400 53240 58564
10 60000 66000 72600 79860 87846 Attribute grenade
Explosive
MSA resistance 1-Increased Increased
20 80000 88000 96800 106480 117128
30 100000 110000 121000 133100 146410 Attribute fire
Incendiary
MSA resistance 2-Normal Normal
40 120000 132000 145200 159720 175692
50 140000 154000 169400 186340 204974 * HP might be increased by skills / items or buffs

Items

The Iron Sentinel uses a selection of unique items unavailable to any other units. Like the parts for the Sentinel itself, these can only be obtained via the Mars Shop (or fused using other items from the same).

Icon Name Stat Effects Components MSA currency Mars Points
MSA item III Rebar Rebar

Production +5
Movement +0.05
Load +5

× 300
MSA item III Morden Symbol Morden
Symbol

HP +500
Resist +5
[Far][Special] Distance +5

× 300
MSA item IV Mars Energy Mars
Energy

Production +15
Movement +0.10
Load +10

× 5,000
MSA item IV Battery Battery

HP +1,000
Resist +10
[Far][Special] Distance +10

x50: MSA item III Rebar MSA item III Morden Symbol

×
MSA item V Missile Missile

Production +30
Movement +0.15
Load +15

× 50,000
MSA item V Big Missile Big
Missile

HP +1,500
Resist +15
[Far][Special] Distance +15

x30: MSA item IV Mars Energy x3: MSA item V Missile

×

Build Up

MSA item I Gnome Bullet MSA item I Bread MSA item I Mushroom MSA Skill small + Strengthen Weapons

Strengthen all attack power by (20%, +1% each level).

MSA item III Rebar MSA item III Rebar MSA item III Morden Symbol

MSA item II Flame Shot MSA item II Apple MSA item II Doll MSA Skill small + All-Around Armor

HP will increase by (20%, +1% each level).

MSA item III Morden Symbol MSA item III Morden Symbol MSA item IV Mars Energy

MSA item III Drop Shot MSA item III Fish MSA item III Fruit MSA Skill small + Equip Anti-Armor

Critical rate for all attacks will become (10%, +0.5% each level).

MSA item IV Mars Energy MSA item IV Battery MSA item IV Battery

MSA item IV Big Flame Shot MSA item IV Bird's Nest MSA item IV Shield MSA Skill small + FORM CHANGE

Even if beaten once, gets back to life and turns in 2nd form via HP (20%, +1.6% each level).

MSA item V Missile MSA item V Missile MSA item V Missile

MSA item V Zantetsu Sword MSA item V Holy Water MSA item V Pants
MSA item V Big Missile MSA item V Big Missile MSA item V Big Missile

Purchase Cost

In order to obtain parts for the Iron Sentinel, surplus parts from platinum-framed units must be traded in at the Mars Shop:

1,000 points are required per Sentinel part. Hence:

  • 1,000x Unit Parts (Normal) grants one Sentinel part.
  • 100x Unit Parts (Rare) grants one Sentinel part.
  • 25x Unit Parts (Super Rare) grants one Sentinel part.

Building on that:

  • 80,000x (Normal parts), 8,000x (Rare parts), or 2,000x (Super Rare parts) grants a silver Sentinel.
  • 180,000x (Normal parts), 18,000x (Rare parts), or 4,500x (Super Rare parts) grants a gold Sentinel.
  • 330,000x (Normal parts), 33,000x (Rare parts), or 8,250x (Super Rare parts) grants a platinum Sentinel.

Furthermore, various items for the Sentinel must also be purchased using Mars Points:

  • 900x (Normal parts), 90x (Rare parts), or 23x (Super Rare parts) grants the first skill.
  • 6,500x (Normal parts), 650x (Rare parts), or 163x (Super Rare parts) grants the second skill.
  • 71,500x (Normal parts), 7,150x (Rare parts), or 1,788x (Super Rare parts) grants the third skill.
  • 221,500x (Normal parts), 22,150x (Rare parts), or 5538x (Super Rare parts) grants the fourth skill.
  • 1,121,500x (Normal parts), 112,150x (Rare parts), or 28,038x (Super Rare parts) fills the fifth panel set.

1,451,500 Mars Points are required to fully evolve and equip an Iron Sentinel (or 36,288 Super Rare unit parts). On the other hand, a silver Sentinel with only the first four skill panels unlocked costs a relatively low 80,000 + 221,500 = 301,500 Points (7,538 SR parts).

One can easily gain massive amounts of the items by hoarding up Battle/Guild Medals and Gold Bars for Battle, Guild and P.O.W Shops. Players should only buy units of the Super Rare rarity, as they provide the best conversion ratio. It is recommended to buy during coin discount sales, as it reduces the cost of purchases by 30%. As waiting for shops to manually refresh is unnecessary, force refresh continually to find Super Rare unit parts. Coins and P.O.W bars can be easily amassed from Extra Ops challenges, high Battle ranking and 2x Gold Bar/Guild Medal events.

Trivia

  • The Iron Sentinel is instead referred to as the "Iron Slider" within Metal Slug Attack's code. Its sprite sheet portrays the original Slider from Metal Slug 6, angled downhill - the game rotates its images to a levelled orientation at run-time.
  • The Iron Sentinel was buffed as of the 2.13.0 update, following player complaints about how weak it was for the time it took to use it properly.
  • The Iron Sentinel was further buffed again as of the 3.8.0 update.
Metal Slug Attack Units
MSA faction Regular Army Utan | Marco | Tarma | Eri | Fio | Slugnoid | Drill Slug | Hyakutaro | Bradley | Elephant Slug | Metal Claw | SV-001 | Soldier | Slug Gunner | Trevor | Nadia | Slug Flyer | Augensterm | Slug Armor | SV-Camel | Leona | Zombie Marco | Slug Copter | SV-001 Experimental | Regular Army Helicopter | Ralf | Ostrich Slug | Donkey Slug | Clark | Trevor (Mummy) | Protogunner | Slug Gigant | Everlasting Summer Eri | Everlasting Summer Fio | Special Nadia | Motorbike P.O.W. | Elephant Slug (Battery) | MS-Alice | "Cat Ears" Leona | Gimlet | Red Eye | Trevor(Monkey) | Nadia(Monkey) | Slug Mobile | Walter Rian | Motorbike P.O.W. Ver.2 | Whip | Slugnoid Type-B | Tyra Elson | Fat Marco | Fat Tarma | Christmas Eri | Heidern | Snowwoman Nadia | Donkey Slug (Eri) | Christmas Fio | Rootmars Slug | Fat Eri | Fat Fio | Drill Slug Ver.2 | Crazy Ralf | SV-001 Type-R(Marco) | Deformed Slug Gunner | Ostrich Slug (Clark) | 6000000taro | Valentine Nadia | Zombie Tarma | Zombie Trevor | MSA (Marco) | Pocket Marco | Jet Clark | Slugnoid Type-Ikari | Anna Wiese | Zombie Fio | Lightning Fio | Zombie Eri | Roberto Nicola | Rumi Aikawa | Special Trevor | 7000000taro | Super Devil Eri | Marco(Monkey) | Fio(Monkey) | Zombie Nadia | Madoka Aikawa | Nathalie Neo | Super Devil Marco | Alisa Stewart | Slug Gigant MK II | Airbone Metal Claw | 8000000taro | Super Devil Tarma | Everlasting Summer Madoka | Everlasting Summer Rumi | Everlasting Summer Nadia | Midori | Special Eri | Regular Army Helicopter MKII | Regular Rocket Bomb Soldier | Orochi Leona | Halloween Whip | Halloween Alice | Special Tarma | Mello | Christmas Midori | Rita | Special Marco | Christmastaro | Amber | Special Roberto | Perche | Special Fat Eri | Nikita | Valentine Fio | Reika | Special Fat Tarma | Golden Slug Gigant | Golden Slug Armor | Ami | Special Fio | Ball Slug | Protogunner Type-B | Molly | Special Fat Marco | M.D.P.S-Mz 3 | Special Mello | 9000000taro | Golden Slug Gunner | Golden Bradley | Louise | Everlasting Summer Rita | Leona Ver.Heroines | Elephant Slug(Ice) | Ostrich Slug(Eri) | Ulala | Special Perche | Gisee | Halloween Nikita
MSA faction Rebel Army Rebel Infantry | Di-Cokka | Nop-03 Sarubia | Karn | Shielded Soldier | Allen O'Neil | T-2B Melty Honey | LV Armor | M-15A Bradley | Rebel Rifleman | Bazooka Soldier | Gatling Soldier | Girida-O | Donald Morden | Shoe | Iron Iso | Iron Nokana | R-Shobu | Hi-Do | Rocket Bomb Soldier | Mortar | Jupiter King | Hairbuster Riberts | Bikers | Patrol Robot | Paratrooper | Rebel Gigant | MH-6 s | The Keesi II | Regimental MH-6 s | Mini Jupiter King | Jupiter King MK II | Airborne Melty Honey | Iron Sentinel | Big Shiee | Arabian Fighter | Arabian Soldier | Camel Rider | Abul Abbas | F.Rebel Infantry | Assy Nero | Kraken | Bull Drill | R-Shobu Ver.F | MH-6 s Ver.F | Crablops | Gen.Morden Ver.Di-Cokka | Allen Jr. | Cabrakan | The Keesi III | Formor | Abigail | Emain Macha | Subway | Allen O'Neil (Wrath) | Union | Scrap Cannon | Elite Arabian Soldier | Tani Oh | Iron Nokana MK II | W.Soldier | Bodyguard (Rebel Infantry) | Bodyguard (Shielded Soldier) | Bodyguard (Rebel Rifleman) | Beatriz | Iron Cab | Eaca-B | R.R-Shobu | Vita | Rebel Infantry (Wrath) | Red Devil Morden | Parachuetruck | Sergeant Drill | Balor | Mortar (Wrath) | Spacey Nokana | Rebel Gigant MK II | Iron Iso II | Iron Vermilion | Dararin Dara Dara | Navy | Special Beatriz | Flying Tara+ | Hodumi+ | Girida-O Ver.F | Nova | Big Gate | Crablops Type-F | Rebel Walker | Everlasting Summer Abigail | Everlasting Summer Beatriz | Drache Macha | Rebel Rifleman(Wrath) | Bazooka Soldier(Wrath) | Shielded Soldier(Wrath) | Tiger Macha | Morden Bus | Destrade | Dragon Nosuke+ | Patrol Robot+ | Shizuka | Special Abul Abbas | Rapid | Special Vita | Huracan | Assy Nero MKII | Elite Arabian Fighter | Elite Arabian Camel Rider | Aisha | Shoe MK II | Karn MK II | Cabrakan MK II | Cabrakan Pod (Individual) | Tani Oh MK II | Di-Cokka MK II | Special Allen Jr. | The Keesi III+ | Formor+ | Julia | Kraken MK II | F.Bazooka Soldier | Chloe | Christmas Nova | Golden Morden | Golden Bikers | Izabella | Special Navy | Golden Nosuke | Golden LV Armor | Frozen Cab | Bodyguard(Rocket Bomb Soldier) | Rogue Gigant | Gatling Soldier(Wrath) | Sister Nokana | Bodyguard(Mortar) | Golden Jupiter | Golden Iso | Grazia | Special Destrade | Red Sergeant Drill | Nop-03 Sarubia MK II | Loretta | Special Huracan | Hi-Do MKII | Girida-O MKII | Big Shiee MKII | Scrap Cannon MKII | Edda | Special Aisha | Cabrakan MK III | T-2B Melty Honey MK II | Dion | Special Izabella | Sky Jupiter King | Mini Jupiter King MK II | Norah | Everlasting Summer Nova | Hairbuster Riberts MK II | Dararin Dara Dara MK II | Emma | Special Shizuka | Golden Nokana | Golden Di-Cokka | K-O3 Coupled Armored Vehicle | Anti Air-Craft | Vicky | Halloween Beatriz | Crablops Type-Lower | Rebel Walker MK II | Abigail (Subjugation Tactics) | Special Chloe
MSA faction Ptolemaic Army Hover Units | Guerrilla | Special Force | Gunner Unit | Shielded Guerrilla | Bazooka Guerrilla | Metal Rear | Sniper | Claw Unit | Girida-O Ver. P.M. | Di-Cokka Ver. P.M. | Special Force (Rider) | Black Hound | Sarubia Ver. P.M. | Ptolemaic Slug | Guerrilla Mortar | Stone Turtle | Bradley Ver. P.M. | R-Shobu Ver. P.M. | MG Unit | Commander | Hover Vehicle | Ptolemaios | Masked Soldier | Dragunov | Flying Tara Ver. P.M. | Sand Marine | A.P.C. (Special Force) | Yoshino | Elite Hover Unit | Caroline | Jupiter Queen (P.M.) | MH-6 s VER(P.M) | Augensterm Ver(P.M) | Ptolemaios (Curse) | Masked Soldier (Curse) | Guerrilla (Captain) | Metal Rear EX | Ptolemaic Slug EX | Special Dragunov | Veronica | Special Caroline | Emerald Turtle | Commander (Navy) | Sisilia | Everlasting Summer Yoshino | Deep Sand Marine | Everlasting Summer Dragunov | Sarubia II Ver.P.M | Caro's Augensterm | Custom Vehicle | Towa | ShootingRay | Union 03 Ver.P.M | Elite Sniper | Mira | Halloween Caroline | Ptolemaios (Abyss) | Gunner Unit(Abyss) | Simon | Special Sisilia | Anastasia IV | Miharu | Christmas Veronica | Union 01 Ver.P.M | Black Hound Type-R | Chunyan | Believer (Master) | Believer (Elite) | Believer (Soldier) | Space Metal Rear | Space MG Unit | Owen | Special Mira | Union 02 Ver.P.M | Special Force (Rope) | Dragunov Ver.Rebellion | Special Towa | Golden Sand Marine | Golden Claw Unit | Sho | Special Yoshino | ShootingRay Ver.Rebellion | Bradley Ver.Rebellion | Maria | Everlasting Summer Miharu | Towa's Augensterm | Girida-O Ver.P.M + | Beecham | Special Chunyan | Golden Turtle | Golden Elite Hover Unit | Damian | Halloween Simon | Land Blowfish | Shielded Guerrilla (Captain)
MSA faction Aliens Mars People | Zombie (Woman) | Hopper Mecha | Mars Mecha | Zombie (Fattish Man) | Zombie (Rebel Soldier) | Tar Man | Ring Laser Mecha | Zombie (Man) | Monoeye | Clone Fio (Zombie) | Clone Eri | Mini U.F.O. | Scientist (Zombie) | Smasher | Crab-Tank | Vanguard | Invader | Hunter Walker | Brain Robot | Dai-Manji | Winged Invader | Mars People Cadre | Rugname | Flying Core | Professor | Tar Man (Red) | UFO Invader | Flying Parasite | Rootmars | Halloween People | Odette | Golden Hunter Walker | Mars People Pocket | Party People Elite | Dark Monoeye | Mars People Elite | Rugname X | Mars Brain Robot | Ring Laser Mecha(Red) | Mars People (Neo) | Annette | Vanguard(Type-A) | Lydia | Mars Professor | Tiny UFO Type:A | Percier | Clone Fio | Monoeye UFO | Clone Abby | Nowan | Everlasting Summer Odette | Dai-Manji (Secret Ver.) | Mini U.F.O. (Secret Ver.) | Halloween Percier | Mars People Officer | Clone Tarma | Clone Betty | Mars People Tank | Mars People Attacker | Mars People Healer | Schwarz Metzelei | Christmas Annette | Rootmars X | Party People X | Ariadna | Special Professor | Fedeln Metzelei | Special Nowan | Cocoon Betty | Ring Laser Mecha(Blue) | Rillacle | Special Odette | Dai-Manji(Ver.Gold) | Mini U.F.O(Ver.Gold) | Gemini White & Black | Clone Marco | Flying Shelt | Ravenous Invader | Halle | Special Clone Abby | Great Mother | Great • Crab-Tank | Franke | Giant Hunter Walker | Smasher Returns | Mars Gigantalos | Special Clone Betty | Snow Monoeye | Zombie(Fattish Man Red) | Mars People Officer(COO) | Clone Tarma(Zombie) | Bonny | Special Black
MSA faction Independent Chowmein-Conga | Ohumein-Conga (Red) | Sasquatch | Mutated Soldier | Man Eater | Mummy | Dog Mummy | Samurai Infantry | Samurai Tanks | Samurai Plane | Big Snail | Giant Caterpillar | Maggot | Flying Killers | Native | Dangling Snail | Bat | Hunged Mummy | Bear | Huge Locust | Mecha Allen | Prototype Iron | Chariot | Pharaoh's Arc | Mummy Warrior | Mummy Cat | Scotia Amundsen | Red Goblin | Japonese Assault Force | Sol Dae Rokker | Morden Robot | Mini Hermit | Pirate Assault Soldier | Pirate Soldier | El Dorado | Amadeus Type:α | Amadeus Robot | Researcher | Slug Armor ver.kusanagi | Slug Armor ver.yagami | Big John | Hazmat Soldier | Native (Bird) | Iron | Vatn | Halloween Soldier | Huge Hermit | Mini Caterpillar | Toschka Dalanue | Sol Dae Rokker (Anima) | Amadeus Corporal | Huge Ivy | Cleopatra | Tyrant Pharaoh | Mummy Generator(Mummy Cat) | Lovely Mummy | White Baby (Prototype) | Mummy (Awakening) | Samurai Infantry (Wrath) | Ohumein-Conga(Green) | Jin | Ghost Shiee | Pirate Soldier(Ghost) | Amadeus Type:γ | Di-Cokka(Amadeus) | Hazmat Soldier(Green) | Jade John | Hi-Do(Amadeus) | Amadeus Soldier (Shield) | Aileen | Special Amundsen | Elysion | Skull Snail | Skull Hermit | Esther | Aswang | Dangling Huge Ivy | Doctor(Brave Guerrier) | Toschka Dalanue II | Amadeus Rifleman | Amadeus Bazooka Soldier | Sea Satan+ | Sarubia (Amadeus) | Sol Dae Rokker(Origin) | Special El Dorado | Elena | Licht | Prototype Iron II | Amadeus Parachute Soldier | Poison Caterpillar | Poison Maggot | Hairbuster Riberts (Amadeus) | Elite Researcher | Iron II | Bradley(Amadeus) | Tyrant Warrior | Dog Mummy(Awakening) | Agalia | Special Vatn | Doctor Type: AI | Amadeus Rocket Bomb Soldier | Cleopatra's Arc | Lovely Hunged Mummy | Alma | Special Aileen | Iron Fortress | Valerian Bear Viola | Valerian Bear Rosa | Valerian Bear Bubu | Real Jhon | Mutated Soldier(Neo) | Ichima | Special Red Goblin | Sea Satan II | Amadeus Mortar | HMT | Arsinoe | Golden Amadeus Type:AI | Golden Morden Robot | First Baby | Special White Baby(Prototype) | Evol Hermit | Flying Killers Type:SSP. | Everlasting Summer Elena | Teresa | Incognito Aswang | Karn(Amadeus) | Shoe(Amadeus) | Kelly | Sol Dae Rokker Arche | Man Eater Arche | Runaway White Baby | Halloween Alma | Golden Fortress | Golden Rosa