Before the events of Super Smash Bros. Tourney, Nightmare met with Raphael Sorel in the Ostrheinsburg Chapel and defeated him. As he stepped forward to kill the man and harvest his soul, Siegfried's mind started to struggle with SoulEdge for freedom. Raphael, watching as Nightmare stood motionless as a result of the mind struggle, released an attack and pierced SoulEdge's eye. This allowed Siegfried to reclaim his body and also released the holy blade SoulCalibur from within SoulEdge. In a state of temporary sanity, Siegfried then drove the holy sword into the cursed Soul Edge and sealed both together, nullifying both powers. However, the will of Soul Edge escaped the sword and entered the dark blue armour that Siegfried quickly discarded after reclaiming his body. Eventually, the mysterious immortal Zasalamel found the armor and created a new body for the immobile Soul Edge out of the countless evil souls haunting Ostrheinsburg. This new Nightmare restarted his reign of terror in search of Siegfried and the rest of Soul Edge, as well as a new host to escape into, as the new body was heavily unstable. Just then, Nightmare encountered Oni Akuma and he entered the Smash Bros. Tourney to stop him by transforming into Night Terror.
The player must complete one of the following requirements to unlock Night Terror:
- Play 900 matches in the Versus Mode.
- Using Nightmare, complete Board the Platforms Level 2.
For both of these options, the player must brawl Night Terror on the Final Destination stage. After defeating Berserker, the announcer will say "Someone else has joined the Tourney!" after a Smash Ball appears on the lower-right corner of the screen with a message saying "You can now use the unstoppable Night Terror. Think you can beat him?". You will then see him to the right of Groudon, above Tron, and below Magnus.
True Soul Wave (Neutral)
Night Terror says "Die, you FOOL!" and creates a shockwave.
True Soul Smasher (Side)
Night Terror swings SoulEdge (Complete) like a hammer and says "CRUSH YOU!".
Allows Night Terror to fly for a short period of time.
True Earth Trample (Down)
Night Terror says "Not gonna happen!" and stomps on the stage's floor, creating a shockwave.
Terror of All Terrors (Hyper Smash)
Based on Nightmare's Soul Calibur V Critical Edge, Night Terror holds his sword up while saying "The terror...", and does one heavy vertical slash to knock his opponent far away while saying "OF ALL TERRORS!".
True Evil Seed (Final Smash)
Based on Nightmare's Soul Calibur IV Critical Finish, Night Terror asks "Ready to DIE?!" and punches his foe with his claw, knocking his foe backwards. Then, he uppercuts his foe into the air while saying "Bow to Night Terror!", he then slams his sword point first into the ground and a ball of energy erupts around his opponent as they are sent flying while Night Terror says "You are defeated!". This move increases his opponent's damage percentages.
- Night Terror moves around while swinging Soul Edge (Complete), all the while saying "I never lose, not to anybody around here!". This victory animation is also called the "I Will Show You The Greatest Nightmare" victory animation.
- Night Terror flourishes Soul Edge (Complete) and poses with it by his side, saying "You shall submit or you shall die!".
- Night Terror flourishes Soul Edge (Complete) and poses with it by his side, saying "You shall regret the day you messed with Night Terror, Dark Akuma!". (Oni victories only)
- Night Terror says "This battlefield was you're last!" and raises Soul Edge (Complete) into the air.
- Night Terror debuted in Soul Calibur III as a secret Tales of Souls boss character, but he didn't become playable until Super Smash Bros. Tourney.
- This makes Night Terror is the only character who isn't playable in the Soul Calibur video games who is first playable in Super Smash Bros. Tourney 1, as many others are set for the sequel.
- The message that appears when unlocking Night Terror in Super Smash Bros. Tourney may reference his extremely hard AI in Soul Calibur III. He is much easier to defeat in Super Smash Bros. Tourney.
- Night Terror shares his English voice actor with Thanos, Khan, Greil, and Thundurus.
- Night Terror shares his Japanese voice actor with Nightmare and Marcus Fenix.
- Night Terror shares both his English and Japanese voice actors with Azazel.
- Oni Akuma is Night Terror's rival in Super Smash Bros. Tourney. The Great Oni is Night Terror's second rival in the sequel.