The Void is presented as the most dangerous being to ever exist in Maginary World and is now in Sonic the Hedgehog's universe. She plans to obtain the Precioustone to give herself "unlimited power". To achieve this, she is playing a "game of cosmic proportions" to defeat Lumina and seize control of everything.
In this story, Sonic is summoned by Lumina and sent to fight The Void in Necropolis. She easily deflects Sonic's attack with an energy shield, so decides to summon her warrior, Turbo, to fight him himself. When Turbo easily wins and demands a rematch, The Void knocks him out for his impudence and throws him in a cell to be punished. It is later revealed that The Void apeared to Turbo some time after he was freed from the Space Race, promising a way to fulfill his thrill-seeking desires.
When The Void "wins" this round of the game, her minions unleash their fury on Lumina's troops. When Sonic and Turbo start trashing her army, The Void begins to unleash her great power to blast everyone "to atoms". Sonic and Turbo's answer is to run up from behind and "punch her out". Lumina is then left to take her back to Maginary World and keep her captive.
The Void seems to take in "olde-world" talk, using long words and interjecting her sentences with defunct synonyms. Reception to this on the Message Zone was fairly negative.
The Void was originally a character in videogame Sonic Shuffle. In this, Sonic, Tails, Knuckles the Echidna, Amy Rose, Big the Cat and Doctor Robotnik are summoned to Maginary World to defeat "Void" (as she is known in this game), and repair the Precioustone. Throughout the game, Void shows signs of loneliness, and they later discover that Lumina and Void are both required to be together to keep the balance of the world right.
In Sonic Shuffle, Void is male, but was made to be female in this strip.