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IsaacHDXxx form2Isaac scribble Rebirth


Gemini full

Boss Gemini

Official artwork by Edmund McMillen
Floor(s) Basement

The Blighted Ovum

Mom's Bra

Mom's Pad
Bob's Rotten Head
Shoop Da Whoop!
Mr. Boom

Item Drop(s) Common Drops

WotL Common Drops

Rebirth Stats
Base HP 140 (Contusion)

140 (Suture)

Stage HP 0

Gemini (also known as simply The Twins from the "Unholy Edition" art booklet) are a set of conjoined twins (parasitic twins) attached by an umbilical cord. 

The large one has two teeth bucked out and is missing an eye with multiple markings.


The larger of the two will walk towards Isaac, trying to deal contact damage. Eventually, he starts charging with increased speed for few seconds. Right after charging, he runs out of breath and has to stop, leaving him vulnerable to attack. The smaller one drifts along at a distance, and will fire fast-moving blood shots at Isaac if he comes near and isn't behind cover. The umbilical cord acts like an elastic tether, keeping them in roughly the same area while not restricting range of movement too much.

Killing the larger twin will cause the smaller one to turn incredibly red when becoming enraged, abandoning ranged attacks in favor of charging at Isaac (if you deliberately focus-fire the small one from the start, it will be killed and you only have to focus on the big one, whose behavior will not change). While enraged, the smaller twin takes a lot more knockback, which can be troublesome if care is not taken.


  • Your best option for handling these two is to run around the edges of the room, firing behind you as you go. Gemini's speed is usually not sufficient to reach Isaac, making him easy to fight.
  • Movement-controlling items like Mom's Bra and Mom's Pad can be helpful if you find yourself unable to stay ahead of the larger twin's frequent charges. Strong explosive attacks like Bombs are easy to land when the large twin stops for breath.

Champion Variants


Gemini green

Gemini starts off with the two detached; however, the smaller one will act as normal. If enraged by the death of the larger one, it does not move as fast as the normal one. However, there is a chance where just the smaller half of him is green. In this case, it's easier on the player, as when it starts its charge, it'll move slower towards the player and is much less of a threat.


Gemini blue

Gemini starts out with increased health, but decreased speed, which is more noticeable if the larger twin is colored. This actually makes Gemini easier, though it takes longer to defeat. As with the Green Champion, there is a slight chance of only the small twin becoming blue, resolving in the older one acting normally, but the smaller twin moving very slowly. Both twins' overall health is increased.


Gemini starts out with two of the smaller twins attached. The first twin comes off when the larger third of Gemini is at half health, and the second comes off when the larger third is slain. While the smaller twins are still attached, they regenerate health, and shoot a spread of three tears.



  • Gemini will occasionally be replaced by Steven after you complete The Basement 25 times.
  • Gemini is named after the starsign by the same name, symbolised by the twins.
  • Gemini appears in the demo.
  • Their individual names are given as Suture and Contusion, with the larger one being Contusion (note the sewn-on patch of skin on his head) and the smaller one being Suture.
  • Their names stem from a cut boss concept (similar to that of Gemini) of Gish, another game from Edmund McMillen. According to Edmund, the larger twin is named Contusion due to the dent in his head, which would make the smaller twin Suture. [1]
  • Gemini may be based on the Twin-to-Twin Transfusion Syndrome (TTTS), which is characterized by joined arteries in a shared placenta between twins. This can result in unequal distribution of nutrition to the twins, leading to a bigger and a smaller twin.


The Binding of Isaac - Isaac vs Gemini FLAWLESS RUN00:57

The Binding of Isaac - Isaac vs Gemini FLAWLESS RUN

Basement Larry Jr.MonstroThe Duke of FliesGeminiStevenFamine
Cellar WidowPinThe Duke of FliesFamineGurdy Jr.The Blighted Ovum
The Caves FistulaPeepGurdyChubC.H.A.D.Pestilence
Catacombs The HuskThe HollowThe Blighted OvumThe Carrion QueenPeepPestilenceThe WretchedGurdy Jr.
The Depths LokiMonstro IIGishWarMom
Necropolis Mask of InfamyDaddy Long LegsThe Carrion QueenThe BloatLokiWarThe WretchedMom
The Womb ScolexBlastocystThe BloatDeathConquestDaddy Long LegsTriachnidTeratomaMom's HeartIt Lives
Utero TeratomaThe BloatDeathConquestDaddy Long LegsTriachnidLokiiMom's HeartIt Lives
Sheol The FallenSatan
Cathedral Isaac
The Chest ???
First to fifth and seventh level The FallenHeadless Horseman
Devil Room Krampus

Start a Discussion Discussions about Gemini

  • Gemini

    8 messages
    • Blue4029 wrote:so i really want to know more about this boss...does anyone have any theories to share? what is contusion anyway...and here is...
    • Blue4029 wrote:so i really want to know more about this boss...does anyone have any theories to share? what is contusion anyway...and here is...
  • Blue Gemini's Item drop

    3 messages
    • This is not exclusive to gemini, all blue champions drop soul hearts upon death.
    • all blue boss champions drop soul hearts. blue enemy champions don't have to.

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