Dark Synchro Summon is the antithesis of a Synchro Summon. Instead of the levels of the Tuner monster and the non-Tuner monster(s) adding up to the selected Synchro Monster's Level, the Dark Tuner monster's level is subtracted from the level of a non-Tuner monster(s), thus making a Dark Synchro Monster. Dark Synchro Monsters are new and unique to the game as they are the only monsters with a Negative Level. This feature is only available in the anime and the video games, Yu-Gi-Oh! 5D's Tag Force 4, Yu-Gi-Oh! 5D's Tag Force 5 and Yu-Gi-Oh! 5D's Tag Force 6
In the anime, when a character Dark Synchro Summons, the white/green stars will go into the monster making it look in pain, and then a number of them unite together in order to have the rest ones be equal to the Dark Synchro Monster's level, which turn black and destroy the monster after coming out and spinning in a circle. Also, the character will say a Dark Synchro chant: "When the shadows are devoured by even darker shadows, the curtain pulls back, and reveals, a world without light!.