"Your short life will soon burn out. With that light, I will suck it all up!"
- ―Dark Mephisto Zwei
Subtitle: Giant of Darkness (闇の巨人 Yami no Kyojin)
A clone of the original Mephisto, Zwei was the latest Dark Giant created by the master of the Space Beasts and Dark Giants. He was created in response to the fact that the original Mephisto's host Mizorogi Shinya was free of the Unknown Hand's influence. The original Mephisto and Mizorogi were no longer puppets. The dark one set events in motion first by returning Mizorogi's memories, in a similarly horrible fashion as the method the former dark Deunamist used on other people. His memories and skills restored, Shinya broke out of Fortress Freedom taking Mizuo of the M.P as hostage. As Hiroyuki Misawa was pursuing Mizorogi as he was escaping Night Raiders' base the Memory Police agent was met by Unknown Hand.
While initially recognizing another member of TLT, Misawa was caught off guard. The dark villain showed his true colors to the boy and made him his slave. As Shinya was cornered, he surrendered to Komon and Nagi only to be shot through the shoulder by Hiroyuki. Hiroyuki showed himself to have been taken over by the darkness and turned into Dark Mephisto Zwei.
Ultraman Nexus came to the scene and the two began their battle first on the ground and then the air. Mephisto Zwei proved too strong for the hero to handle and fast enough to keep up with the third Deunamist. Ren was kick into a cliff and pinned down as Zwei attempted to drain him dry of his energy.
"You should already...have lost the ability to transform!"
- ―Dark Mephisto Zwei
As Mephisto Zwei started to absorb Nexus's energy, Shinya morphed into Dark Mephisto and saved Nexus. Mephisto appeared to have the upper hand as he fought Mephisto Zwei until he was impaled with the impostor's version of the Mephisto Claw. As his dying action Mephisto held Mephisto Zwei in place for Nexus to use the Arrow-Ray Schtrom to reduce the impostor to blue particles. At the end of the battle revealed that he and Mephisto were both puppets of the Unknown Hand despite Mephisto's use of agents and his diabolical plans. Mizorogi outright confirmed this before his death.
- Height: 50 m
- Weight: 50,000 t
Hiroyuki Misawa (三沢広之 Misawa Hiroyuki): He was part of the Memory Police that fell under control of the Unknown Hand. He has the same powers as Dark Mephisto and only differs in eye color with Zwei being red instead of black. Thanks to the interference of the original Dark Mephisto, now on the side of good, Zwei is destroyed by Nexus. After Zwei was destroyed, Hiroyuki died within him as well.
Being a clone of the first Mephisto, he transform in the same way. Hiroyuki uses the Darkevolver, where he pulls the two ends of the device apart, and transforms into Dark Mephisto Zwei in a dark pillar.
- Speed: Zwei has greater speed and agility to keep up with Nexus' Junis Blue, unlike his template.
- Strength: Zwei is apparently much stronger than his predecessor. Even accounting for his injuries Zwei was easily able to overpower the original Mephisto.
- Mephisto Claw (メフィストクロー Mefisuto Kurō): Zwei also uses the claw form from the modified Armed Mephisto on his right arm.
- Dark Phalanx (ダークファランクス Dāku Farankusu): Zwei rapidly attacks the enemy using his Mephisto Claw.
Dark Mephisto Zwei as his name implies, is a clone of the original Dark Mephisto. In theory he has all the same powers, abilities and attacks as the original Mephisto but only demonstrated the following attacks:
- Dark-Ray Schtrom (ダークレイ・シュトローム Dākurei Shutorōmu): Same as the original but was never used.
- Dark Ray Feather (ダークレイフェザー Dāku Rei Fezā): Zwei can fire arc shaped bursts of energy, just like his template. However, Zwei can fire it in three consecutive bursts.
- Burst Cluster (バーストクラスター Bāsuto Kurasutā): Zwei uses the same Dark Ray Cluster attack as his predecessor. Unlike his template, his has a homing effect.
- Dark Flame (ダークフレイム Dāku Fureimu): Zwei can fire an energy blast from his right hand. Can be fired in succession.
- Energy Drain: Zwei can absorb the energy of other beings. Something the original never exhibited.
- Ultraman Nexus (Junis Blue) VS Dark Mephisto Zwei (Play Hero VS 2-pack, 2005)
- Release Date: December 2005
- Price: 300
- JAN/ISBN: 4543112332004
- Materials: PVC (figures)
- Released as part of the Play Hero VS "Invasion! The Strongest Enemy" lineup, this Dark Mephisto Zwei is a small figure (about 8cm) and he sports 3 points of articulation and entirely casted in red plastic with black, silver and gold paint operations. He also comes with Ultraman Nexus Junis Blue.
- Package images with Nexus & Dark Mephisto Zwei includes the said figures.
- Dark Mephisto Zwei (Ultraman Heroes Single Packs)
- The Dark Mephisto Zwei figure is also available individually in a windowed bagged packaging outside Japan.
- Zwei is German for two, referring to how he is the second Dark Mephisto.
- Despite his supposedly greater power Zwei appeared to have been losing against his template. It is argued by fans that without his prior wound Mizorogi could have defeated him.
- When Zwei first rose, he looked the same as the original Mephisto, but his eyes turned red after Ultraman Nexus appeared and struck him.
- Despite his real name being Dark Mephisto Zwei, he is only refered to as Dark Mephisto in the series, at the end, Zagi only mentions Faust and Mephisto, either not caring or grouping the two together.
- He and Dark Zagi are the only Dark Giants in the series never to help the protagonists in Ultra form. Coincidentally, the Ultras who helped the protagonists have black eyes and had more than one appearance, and the Ultras who didn't have red eyes had a single appearance.