|Romaji||Midorii no Yugudorashiru|
|Light Novel Debut||Volume 1|
|Manga Debut||Chapter 4|
|Anime Debut||Episode 3|
'Green' Yggdrasil ('緑'のユグドラシル, 'Midorii' no Yugudorashiru) is one of the Dragons that appear in the Unlimited Fafnir series. Although initially an ally to Yuu Mononobe, it eventually attempted to seize control of his body, leading to its defeat at the hands of the Dragon Subjugation Squad.
Yggdrasil's main body has the appearance of a giant tree and is capable of moving by generating legs.
Yggdrasil is shown to communicate in a way similar to a computer program, with minimal words and emotionless delivery. Like a machine, it always gauges its options and picks the response it considers appropriate for the situation. However, Yggdrasil is capable of emotional responses, as it can feel fear and was driven by the instinct of self-preservation. Yggdrasil prioritized its survival above anything else and would go as far as to kill anyone who would sabotage its plans.
At an unidentified point in the past, Yggdrasil succeeded 'Verdant' Kiskanu by inheriting its Authority after the latter perished in the battle against the Seventh True Dragon, 'Disasterification' Apocalypse. Aware of the fact that the world would be completely destroyed by the coming Ninth True Dragon, Yggdrasil sought ways to increase its chances of survival. After the Dragons emerged in the modern world 25 years before the start of the story, Yggdrasil's main body settled in the border between Germany and Denmark. Because of Yggdrasil's presence, 'Black' Vritra was forced into hiding, since the two's goals were fundamentally different and Yggdrasil was Vritra's natural predator.
At some point in time, Yggdrasil became convinced that Yuu Mononobe was Neun, the Ninth Counterdragon born to oppose the Ninth True Dragon. Seeking to obtain him in order to possess his antibodies that could resist the ninth calamity, Yggdrasil contacted Yuu when the latter's hometown was under attack by Hekatonkheir, offering him power in exchange for his memories. When Yuu accepted the deal, Yggdrasil granted him blueprints for the Special Artillery, Megiddo, but also transfered something akin to a computer virus into his brain with the intent of eventually assuming complete control over his body.
In Volume 2, when the revived Hekatonkheir attacked Midgard, Yggdrasil aided Yuu by activating Code Vier, Leviathan's Authority. This enabled Yuu to utilize antigravity in order to push Hekatonkheir towards the sea, where he was able to destroy it with his Anti-Dragon Armament without consequences.
In Volume 4, Yggdrasil also aided Yuu in destroying 'Yellow' Hraesvelgr in the Principality of Erlia by granting him the Psionic multi-barreled cannon Noah that could overcome its Ether Wind, blocking all of Yuu's remaining memories from his birth up to three years ago as compensation.
Eventually, Vritra created another Hekatonkheir and set it against Yggdrasil in Volume 5. Although Yggdrasil's main body was destroyed, it merely moved its consciousness inside Yuu's body. While there, Yggdrasil attempted to kill Loki Jotunheim for threatening it by taking control of Yuu's left arm. Later, he almost killed Lisa Highwalker in the same way for having discovered the truth behind Yuu's condition. However, it was stopped by Charlotte B. Lord, who used her Authority of domination to prevent Yggdrasil from further taking control of Yuu's body. Yggdrasil, taking the form of a vine, escaped to Midgard's grounds, taking Iris Freyja, Firill Crest, Ren Miyazawa and Lisa's parents as hostages. It then headed back to the academy, having taken the form of a large tree, in order to retrieve Yuu. In the ensuing battle, Yuu saved the hostages, but was unable to deal decisive damage to Yggdrasil due to the latter's ability to absorb dark matter and interfere with machinery. However, when Yggdrasil injured Yuu while attempting to kill Iris, the latter awoke 'Red' Basilisk's power, Catastrophe, using it to destroy Yggdrasil's proxy body. In the aftermath of this battle, Yggdrasil moved to another body in Japan's Mount Fuji, having determined that Vritra was hiding in Japan during its battle against Hekatonkheir. There, it captured Vritra, using her as a source of energy to accelerate its growth.
Eventually, Yggdrasil engaged in battle with the Dragon Subjugation Squad in order to obtain Yuu in Volume 6. Although Yggdrasil's interference with dark matter prevented everyone from approaching it, Tear Lightning was able to create an electromagnetic barrier after Kili Surtr Muspelheim performed the final modifications on her horns, enabling the Dragon Subjugation Squad to enter Yggdrasil's zone of interference uninhibited. Upon arriving there, Yuu used Hraesvelgr's Authority, Ether Wind, in order to materialize Yggdrasil's soul with assistance from Ren. Afterwards, he proceeded to fire upon Yggdrasil's soul with the Noah turret. Although he was unable to destroy it, he caused enough damage to allow Tear to hack its core and tamper with its systems. As a result, Tear became the new core of Yggdrasil, inheriting its Authority.
Powers and AbilitiesEdit
Akashic Record: Yggdrasil's Authority, Code Zwo, enables it to amass and process all information observed by Yggdrasil through its plant network, making it essentially a biological computer consisting of all plant life in the world. As a result of this, Yggdrasil is nearly omniscient and cannot be destroyed unless all plant life in the world is wiped out, since it can merely transfer its consciousness to another plant.
- Electricity Manipulation: As a side effect of its ability to manipulate information, Yggdrasil can control electricity. It has been shown to use this power to shut down machines and even launch attacks comparable to a railgun by accelerating objects through an electromagnetic field. However, the most prominent use of this power is Yggdrasil's ability to hack into dark matter. Since dark matter is influenced by thoughts, which are essentially electric signals, Yggdrasil can merely send out stronger electric signals to hijack the dark matter, using it as an energy source or shaping it through biogenic transmutation into organic matter. This ability makes Yggdrasil a natural enemy to Vritra and all Ds in general.
Over the course of the series, Yggdrasil helped Yuu in his battles against other Dragons by downloading blueprints of weapons for him to create in his mind, but had been blocking more of his memories with each deal they made. Yggdrasil viewed Yuu as nothing more than a vessel for him to control so he could survive the ninth calamity due to his belief that Yuu might be Neun, the Ninth Counterdragon.
- Yggdrasil is the name of a giant tree in Norse Mythology that connects the Nine Worlds.