Nightmare (Japanese: ナイトメア, Hepburn: Naitomea) is a fictional character and the main antagonist of the Soulcalibur series of video games.

During the development of Soulcalibur, Nightmare's helmet went through several iterations with an aim to give a sense of "pressure" and "emit an atmosphere that terrifies anyone who sees them.

"[5] The finalized design was modeled after a unicorn, while his armor implemented imagery of a dragon, which the development team felt symbolized "evil, chaos and power".

Said mutated left arm originally took inspiration from a fiddler crab, giving what the developers felt was a "heteromorphic" appearance to the character.

[6] As for the weapon itself, while at one point they considered a coiled lance, most iterations kept the large zweihänder sword Siegfried had used in the original Soul Edge.

Earlier drafts of it were given red pores and veins, meant to resemble a plant and to let one "feel the beauty even in the midst of fear" when looking at it, while elements such as a mouth and eye were added to give it a more organic appearance.

Allying himself with Astaroth, Ivy, and Lizardman in the city of Ostrheinsburg, Nightmare attempted to completely restore Soul Edge.

Created as an avatar for a disembodied Inferno using the original armor as a shell, he pursued and eventually recovered his true body, Soul Edge.

At the moment the swords struck a burst of energy was released; Siegfried was mortally wounded, while Soul Edge and its body were pulled into a warped dimension, eventually returning to Ostrheinsburg.

Nightmare would then clash against Siegfried in a final duel, though his plans were interfered with the appearance of Algol and the Tower of Remembrance.

From there, Dumas works his way into the graces of the Holy Roman Emperor Rudolf II and is installed as the ruler of Hungary.

Dumas manipulates one of his soldiers, Patroklos Alexander, into killing people corrupted by Soul Edge known as Malfested in exchange for help in his search to find his missing sister, Pyrrha.

Nightmare then initiated a war throughout Europe with his newfound power, but is eventually struck down and killed by Z.W.E.I., a young man whom he previously tried to hunt.

[8] In 2003, Todd McFarlane Productions released a Nightmare sculpture amongst a set of five based on characters from Soulcalibur II.

[11] In August 2003, Todd McFarlane Productions released a Nightmare sculpture amongst a set of five based on characters from Soulcalibur II.

[14] IGN listed him as a character they wished to see in Super Smash Bros. Brawl as a playable guest villain, though noted he was also "too extreme" for the series.

[17] In a 2002 poll by Namco prior to the release of Soulcalibur II regarding their favorite character, Siegfried placed ninth with 2.5% of the tally, tied with Mitsurugi.

[19] In a retrospective of how his design evolved between the along the course of the series, Cecilia D'Anastasio of Kotaku stated "When I was a little gaming baby playing SoulCalibur II, Nightmare’s demonesque appearance and weird sentient sword freaked me out."