The Fate System's plan was pretty simple. Destroy a few of Mystique's worlds, cause them to latch onto the Serpent Universe, and turn every sentient creature within to go insane.
Adding onto this, he forced the insane underlings of the Invader System to recklessly march towards the 24 Rings world, pressuring Stencil and Rhizen further. It prevented them from doing anything else for the time being.
He invited Slayer to the Serpent Universe, and using the key that controlled the Serpent Universe, he allowed Gehera to sense Slayer's aura. And as this happened right after the madness infection, Gehera lost her mind to rage and rushed towards the mouth.
Using the dragon plushies, Gehera teleported to the forefront of their battleground. She didn't even require their permission. With a swing of her hand, she devoured the powers of one, using which she crossed half the Serpent Universe.