"The Approaching Threat! A Mysterious Visitor" is the one hundred and fifty-seventh episode of the Yu-Gi-Oh! GX anime. It first aired in Japan on October 17, 2007. The episode was never dubbed, but became available to the world with official subtitles via Crunchyroll on August 23, 2016.
Having ended his conflict with Yubel, Jaden returns to Duel Academy in order to complete his third and final year there. Duel Disks cease to function properly, and a new enemy appears.
At the Slifer Red dorm, Jaden is napping. The spirit of Professor Banner appears and pesters him, while Jaden questions why Banner's ghost has not yet passed on. Banner responds he's more comfortable this way. Pharaoh arrives with a package for Jaden, which contains a red cell phone. Activating it, the person on the other end of the line informs him of something, which Jaden seems intrigued by.
At the card shop, complaints are coming in about the holographic technology of the Duel Disks no longer working. Students begin attempting to return large amounts of cards, thinking they are defective. Chazz and Alexis arrive at Chancellor Sheppard's office. Sheppard reveals he's called both Industrial Illusions and KaibaCorp in regards to the cards and the Duel Disks, respectively. With their representatives coming, Sheppard assigns Chazz and Alexis to gather up all the cards that are not working. They state they themselves have not encountered problems.
On Duel Academy's roof, Chazz and Alexis meet with Syrus, Hassleberry and Yusuke Fujiwara. Syrus offers to take Hassleberry and gather the defective cards from the Ra Yellow dorm. Alexis goes to the Blue dorm, while Chazz and Fujiwara head towards Duel Academy's computer center. It's revealed that Jaden is the sole inhabit of the Red dorm at this point, implying everyone else was promoted. On their way to the Yellow dorm, Syrus asks Hassleberry who Fujiwara is, and the latter responds that he's been one of Syrus' best friends since his first year.
At the computer center, Chazz also questions who Fujiwara is. The latter's eyes glow red, and he states that they've been friends for three years. He suggests Chazz that go to help Alexis at the Blue dorm, letting him handle the computer system. Chazz agrees and leaves. Fujiwara discovers information about the Abandoned Dorm, and he thinks it could be the key to finding his "master". Alexis contacts him on his PDA and tells him to come to the conference room. Once there, Fujiwara sees a dark aura surrounding the cards, which the others cannot see. He suggests they burn the cards, and the others decline. That night, Fujiwara sneaks into the room where they cards are being held, and burns them.
The school's sprinkler system and a fire extinguisher wielded by Hassleberry put out the fire, but not before most of the cards are burned. Those that remain still exhibit a dark aura, which rises up and combines, and exits the school. No one appears to be able to see this dark aura but Fujiwara and Winged Kuriboh. The latter flies off to inform Jaden. Fujiwara arrives at the Abandoned Dorm, but is chased off by the dark aura. Jaden intervenes and tells the aura to show his true form. It comments that he didn't expect any humans to be able to see it. The form changes, and a dark-clothed figure appears, who activates a Duel Disk.
Jaden easily wins the Duel in two turns, and his opponent disappears, though he has never seen the man's "Dark Archetype" card before. His voice rings out and states that this is only the beginning, and that they will surely meet again. Jaden questions who Fujiwara is, and the latter's eyes glow red once more as he claims they've known each other for years. Jaden's own eyes change colors - to the same bichromatic style of Yubel and he claims Fujiwara's "cheap tricks" won't work on him.
Turn 3: Trueman
Trueman draws "Axe of Despair" and subsequently activates it to equip the latter "Reign-Beaux" and increase its ATK by 1000 ("Reign-Beaux": 2500 → 3500/1800).
"Reign-Beaux" attacks "Neos", but Jaden activates his face-down "Hero Shield" and equips the latter to "Neos". Jaden then sends "Hero Shield" to the Graveyard in order to prevent "Neos" from being destroyed (Jaden 4000 → 3000). The last effect of "Hero Shield" then activates, allowing Jaden to draw one card (as he took 1000 Battle Damage).
Turn 4: Jaden
Jaden draws. He then activates "Neo Space". Now "Neos" and Fusion Monsters that list "Elemental Hero Neos" as a Fusion Material Monster will gain 500 ATK ("Neos": 2500 → 3000/2000). Jaden then activates "Neos Force", equipping it to "Neos" and increasing its ATK by 800 ("Neos": 2500 → 3800/2000). Now if "Neos" destroys a monster by battle and sends it to the Graveyard, Trueman will take damage equal to his destroyed monster's ATK. "Neos" attacks and destroys "Reign-Beaux, Overlord of Dark World" (Trueman 1500 → 1200). The second effect of "Neos Force" activates (Trueman 1200 → 0).
The following cards appeared in this episode. Cards in italics debuted here.