The Duel took place, as Kaiba attempted to ascend to the netherworld to face Atem. Sera warned him of the dangers and imposed a Duel in an attempt to stop him.
Kaiba set up the Duel Links virtual world, where he gathered Duelists' consciousness via Neurons. He intended to rule this world as king. He hoped that assembling high levels of consciousness would enable access to other dimensions, including the netherworld, where he could face Atem. Sera was aware of these intentions and approached Kaiba at his house. She claimed to have heard the voice of an important person, residing in the netherworld, while in the Duel Links world. She began to suggest that Kaiba could do something by syncing with this superior consciousness, but disappeared just before Kaiba received word of unusual activity in the Duel Links.
Mokuba Kaiba informed Kaiba of unfamiliar data registering on their main branch laboratory's Duel Links surveillance monitor. He showed Kaiba how test subjects' Neurons signals were following an abnormal pattern and being drawn towards an unknown consciousness. Kaiba recognized this as the dimensional ascension he had been looking for and logged into Duel Links via his VR pod, much to Mokuba's concern.
Inside Duel Links, Kaiba flew his "Blue-Eyes White Dragon"-themed jet towards the higher-level dimension, where Atem was. However, Sera, masked by her avatar flew next to him. She warned him of the danger he was approaching and asked if he was prepared to face a world of evil, transcending the boundaries of mortal man. Kaiba asked if she was questioning if he had fear in his actions and warned her that anyone who stood in his way would be mercilessly eliminated. She offered to let him proceed if he could defeat her, the holder of the superior consciousness, in a Duel and warned that he would die if he lost. Kaiba replied that this was interesting and accepted.
"Duza" attacked "Blue-Eyes" and Sera thought she had easily defeated it. However Kaiba offered one piece of criticism in Sera's lack of consideration and suggested that she might still be a child, who needs to learn how to better control her consciousness. The ATK of "Blue-Eyes White Dragon" rose to 5900 Pulse, due to Kaiba controlling his though frequency and then to 19900 Pulse. "Blue-Eyes" destroyed "Duza", reducing Sera's Life Points to 0, causing her to lose.
The design of Sera's avatar faded away, leaving her assume her regular form. She was slightly upset over losing an avatar she had been fond of.
Having been defeated, Sera ceased efforts of trying to stop Kaiba and accompanied him, stating that there was no turning back now. Although they succeeded in approaching Atem, they were logged out of Duel Links, as Mokuba performed an emergency shutdown, as the amplified brainwave activity put Kaiba's life at risk.