Gradius Wiki
Gradius Wiki

Big Core MK III (ビッグコアMk-III Biggu Koa Mk-III?) is a recurring boss in the Gradius series.


Big Core MK III is the third boss to be dubbed Big Core and it debuted in Gradius III. It is drastically different than either of the two previous ones. As you may have already guessed, this one has three cores to destroy. The SNES version of Gradius III calls this QB2B.

Attack patterns

Big Core MK III attacks by opening up and shooting lasers out of it's wings. Then a reflective laser shoots and bounces off of the giant lasers. If the front cores are destroyed, then the reflecting lasers are exchanged for mini lasers. When closed, it fires five lasers, unless the front two cores are destroyed, then it fires four lasers (either the traditional Big Core MK I pattern or two normal and two semi-auto). When you get above or below it, it fires four lasers behind itself, and eventually it will move towards the left side of the screen and attack you with them.

Big Core MK III in Gradius IV is actually a slightly modified version called Big Core MK III Kai(改). It has ability to change the angle of its wing, making its laser attacks more confusing. Since the Big Core MK III in Gradius V wasn't the 'Kai' version, it didn't have this ability.

Gradius V adds some new tactics. First, it will attempt to ram you similar to Big Core MK II. Now the player have a chance to destroy the back core directly. There are new attacks here as well. It will shoot straight lasers and homing lasers out of the wings while shooting bullets and sometimes, even turn around to attack regardless if the front cores are destroyed.


Gradius III
Ships Vic Viper
Stages DesertBubble ZoneVolcanic PlanetHigh Speed DimensionMoai ZoneCell PlanetProminence PlanetPlant PlanetCrystal ZoneBoss RushMechanical Base
SNES exclusive stages High Speed ZoneFortressCell
Bosses GoliathBubble EyeGodreiBig Core MK IIIDogasVaifTwin Vaif (SNES) • GregolWyvernVulture DragonChoking WeedLizard CoreBeacon (SNES) • TetranCovered CoreBig Core MK IICrystal CoreDeath MK IIDellinger CoreDisruptShadow GearShadow Gear MK II (SNES) • Big CoreGolemBacterian
Gradius IV: Fukkatsu
Ships Vic Viper
Stages Liquid MetalPlantBubbleMagmaMoaiCellHigh SpeedBoss RushFinal Fortress
Bosses Yorogaton ChimeraDendrodiumBubble CoreGilladorAlpha/OmegaBerialRolling CoreVanishing CoreBig Core MK IIICovered TetranBerserk CorePlanet CoreBloody GateCrab-IIGofer
Gradius V
Ships Vic Viper T-301
Stages Planet Gradius Satellite OrbitPlanet Gradius City Sky APlanet Gradius Urban Underground HierarchyBacterian Cell CenterAsteroid Front BaseBacterian Multiplication PlantBacterian Fortification CenterPlanet Gradius City Sky B
Bosses Big Core MK-I Rev.2Venom (lower) • Death MK IIITetranBig Core MK IIBig Core MK IVGround SpiderHuge HeartBlaster Cannon CoreRolling CoreCircle CoreBig Core MK IIICovered Core MK IIBeaconKeeper's CoreElephant GearVenom (upper)
Core Warships
Big Cores Big Core MK IBig Core CustomBig Core MK-I Rev.2Big Core MK IIBig Core MK II KaiBig Core MK IIIBig Core MK IV
Big Core variants BeaconBig Core DuoBlaster Cannon CoreBubble CoreCircle CoreCoreshipCrater CoreCrystal CoreDellinger CoreDesert CoreHeaven's GateJuggler CoreLaser CoreLizard CoreNeo Big CorePerla MeraldaRexion CoreRolling CoreShining CoreSuper Big CoreTerra CoreVanishing CoreGenocide CoreOdin Core
Core-style bosses Abaddon WarshipCovered CoreCovered Core MK IIDead EndKrakenMayhem WarshipMetal SlaveMisfit WarshipQueensrÿcheRiot WarshipPlate Core
Pseudo-Cores DeathDeath MK II (DeathDouble) • Death MK IIIBeta CoreNobilTriple CoreCrash Bam
Tetran variants Tetran (Zylom) • Covered TetranCrystal Core D-X02Laser TetranTenny Rop
Parody Cores Candy CoreDecoration CoreDecoration Core MK IIViva Core