New Testament SD Gundam Gaiden: New World Advent Legend (新約SDガンダム外伝 新世聖誕伝説?) is a media project within the SD Gundam franchise produced in 2017, centered on Bandai's Gunpla and Carddass trading cards.
The twelfth Knight Gundam series, it takes place between Shin SD Gundam Gaiden: Gaitoshin Senki and Saddrac Knight Saga. It uses designs mostly from Mobile Suit Gundam IRON-BLOODED ORPHANS. In addition, the story sheds light on the moon kingdom Selenis and the ancient moon war that lead to its fall, which was first mentioned in Kikōshin Densetsu.
A few years after the final battle between Gaitoshin Wing and Baroqugun, a new threat arises. The moon suddenly becomes red and the previously inactive D-Dolls reactivate and attack the Kingdom of Lacroa. Along with their sudden reactivation comes Divine Knight Wing, currently half of the Guardian God Sunborn, and Selenis Knight Neo Gundam, pilot of Elgaia and Shuffle Knight, who arrives to explain that Saddrac is being targeted.
- Iron-Blooded Knight
Shortly afterwards, a strange knight appears. The knight, known as Knight Gundam Barbatos, attacks Neo Gundam so he could "die for his sins", which confuses the latter. During their fight, he happens to see an aristocrat named Kudelia, becomes distracted, and is defeated by the mysterious Masked Knight. Masked Knight had been brought back earlier by Warrior Trowa and Fencer Wu Fei. Barbatos is captured and imprisoned. During a visit from Kudelia and Neo, he explains that Kudelia is actually a descendent of those who escaped the moon during the war with the Gjallarhorn Empire and calls Neo a traitor for deserting the people. Suddenly, Lacroa Castle is attacked by Gjallarhorn's forces and Neo heads out in Elgaia. With help from Kudelia, Barbatos puts aside his grudge to fight Gjallarhorn. It's then revealed that Masked Knight was a Gjallarhorn spy and he summons Stranger God Delgaia, a machine soldier developed by Gjallarhorn based on Elgaia's data. Delgaia then transforms into Crest Gungenesis and fights Elgaia and Divine Knight Wing. Both are overwhelmed, but God Gundam appears to give Neo the God Sword. The strength of the God Sword causes Crest Gungenesis to take heavy damage and it retreats with Masked Knight. However, the God Sword's strength damages Elgaia to the point where it goes into stasis. In order to resurrect it, Neo, Kudelia, and Barbatos go on a journey to find the other five Armor Gods.
- Burn! Fierce Fight of the Armor Gods!
Neo, Kudelia, and Barbatos go on a journey to find the five Armor Gods and use their Elemental Power to revive Elgaia. To help escort Kudelia, Knight Barbatos brings along Tekkadan, a mercenary force made up of the descendants of the people of the moon. They first travel to a volcano where Mercarius and Aquarius are and meet up with Silhouette Lord F91. While there, they fight Revenge Monster Zactopus and Barbatos is given strength by the two Armor Gods. Afterwards, the group travels with Sandrock and Quattre to the desert to find Orphius and Jupiterus. While there, they are attacked by Gjallarhorn commander Kimaris and his forces. During this difficult battle, they are assisted by Stamen in the Armored Chariot Orchis. Using the chariot as inspiration, Barbatos uses alchemy to create a power up to allow himself to fight Kimaris more easily. The last Armor God, Gigantis, was in Edmonton Country's Machine Soldier Valley. Waiting there was Gigantus, who was under the influence of evil from the last great battle. Masked Knight appears to take advantage of this by using Gigantis to take control the other Armor Gods. After being persuaded by Kudelia, Barbatos lends Neo his power. At that time, the parts given to him by Sunborn activated and purified the evil energy around Gigantis and the other Armor Gods. The five of them defeat the Stranger God that had appeared and cause Masked Knight to retreat. Afterwards, Neo has a brief vision of Elgaia's new form.
- Crimson Moonlight and the Prince's Armor
After succeeding in finding all five Armor Gods, the group stops in Chryse Village on their way back to Lacroa Castle. However, they are attacked by Gjallarhorn, who attacks the village in new Machine Soldiers. Barbatos also successfully resurrects his allies Machine Warrior Gundam Gusion Rebake and Machine Mage Flauros. Reenforcements arrive from Lacroa in the form of Knight Domon and King Shuffle, which allows Barbatos and the others to escape to Lacroa Castle. When they arrive, they see that Lacroa Castle is under attack by Gjallarhorn. The fight of the iron blooded knights has begun. Kudelia and the others run into danger when they are attacked by Kimaris and Masked Knight. Wing assists them and breaks through Masked Knight's mind control, which reveals that his true identity is Gjallarhorn's Prince, McGillis. Meanwhile, Neo gathers the Armor Gods' Elemental Energy and resurrects Elgaia. Suddenly, Gjallarhorn's commander, Commander Rustal appears and reveals his true form, Bug Rustal. In response, the six Armor Gods combine into Gungenesis. The confrontation between Gungenesis and Bug Rustal has begun. Bug Rustal is defeated by Gungenesis, but the red moon then begins to emit a strange aura, drawing everyone below towards it.
- Shining Iron Blooded Devil in the Moon
Those within Lacroa Castle were taken into the moon, where they appeared to be in some kind of subspace. The Neo, Wing, and the Iron Blooded Knights then split up to find and defeat the true enemy, the Evil of the Moon. While Wing and Neo broke through the enemy's formation, Barbatos and the other knights advance and discover Zeon Black Castle, the former base of Satan Gundam. Within this castle were mechanical monsters formed from the memories of the land of Lacroa. During this time, McGillis restores his Ahab mail, becomes Knight Captian Bael, and frees Kimaris from his brainwashing. The knights then advance to the final battle against the Evil of the Moon, which had been fully revived...
Soldier Mikazuki/Knight Gundam Barbatos→Iron Knight Gundam Barbatos Lupus→Iron Knight Gundam Barbatos Lupus Rex
- Design Basis: Mikazuki Augus, ASW-G-08 Gundam Barbatos, ASW-G-08 Gundam Barbatos Lupus. ASW-G-08 Gundam Barbatos Lupus Rex
The main protagonist of the story. A knight who had been hunting down Neo Gundam. Similar to how Angel Heero transforms into Knight Wing Gundam, Soldier Mikazuki uses the Ahab Mail to transform into Knight Gundam Barbatos. However, he is unable to at this time without Sunborn's forehead parts.