Fighting Fefnir

Fighting Fefnir, known in the Japanese version as "Tōshō" Fafnir (「闘将」ファーブニル), or simply Fefnir, is a video game character in the Mega Man Zero video game series. Fefnir is the leader of Neo Arcadia's Jin'en Gundan ("Army of Ash Flames"). Fefnir's schematics were based on that of X's capabilities of ground combat. He is one of the Four Guardians (四天王) designed to protect Master X. He wields two arm cannons, named Sodom and Gomorrah (ソドムとゴモラ). He was fiercely faithful to Master X and oversaw a pupil, Anubis Necromancess III.

Design
Like his siblings, his armor is based on that of his biological origin, X, with thematic alterations. Fefnir's armor is colored red, symbolizing his alignment with the fire and earth elements; his overall design is derived from his namesake, Fafnir, a wingless dragon from Norse mythology (not to mention his name in Japan is Fafnir). Unlike his fellow siblings and X, he does not wear the familiar 'X' shirt they share in his design, instead wearing armor with large shoulder pauldrons. The yellow spikes on his chest and helmet resemble the protruding fangs of a dragon's snout, and his arm cannons bear a distinct jaw motif. Fefnir uses his arm cannons for flame-based attacks, one of which incorporates firing a barrage of flames into the air, which then rain down from the sky, resembling the destruction of the biblical cities of Sodom and Gomorrah, from which his weapons' names are derived.

In his Armed Phenomenon form, Fefnir's armour expands to become a large tank equipped with cannons and flamethrowers, all of which bear a distinct dragon motif, further emphasising his mythological inspiration.

Personality
Fefnir loves battle, and he gets disappointed upon being told to step back. Like the other Guardians, he is unquestioningly loyal to X, though he may not be quite as fervent in this loyalty as Phantom was. He is proud of his position in Neo Arcadia and sees it as a true peaceful utopia, a position ironic due to his own love of violence, but one he holds nonetheless. Fefnir sees Zero as a rival mostly due to his skill in battle, but he envies Zero's past with X as well.

Story
When X sealed the Dark Elf after the Elf Wars, the shock forced X's soul from his body, and it split into five Cyber-elves. Four of these Cyber-elves were used to create Hidden Phantom, Fairy Leviathan, Fighting Fefnir and Sage Harpuia, while the other wander around Earth. The four work to Neo Arcadia to clean the pollution caused by the Maverick Wars.

At some point, Fefnir, along with his three siblings, became military generals of Neo Arcadia, responsible for the overall safely of Neo Arcadian inhabitants, both humans and Reploids. Fefnir became the leader of the Jin'en Army, Neo Arcadia's land forces. The Mutos Reploid Anubis Necromancess belonged to his forces, and Phoenix Magnion was relocated to his army after Phantom's decease in Mega Man Zero 2.

Mega Man Zero
After Anubis was defeated by Zero in the first Mega Man Zero game, Fefnir launched an assault on the Resistance Base, going through the treacherous desert in which his pupil was destroyed. This assault was thwarted by Zero and he himself was defeated. He was defeated again by Zero in Neo Arcadia's Area X, but rose again to defend the Inner Sanctum where Copy X resided. He was told, along with the other two Guardians (Phantom self-detonated earlier), to step down by Copy X as he appeared before Zero himself. Copy X was destroyed later.

Mega Man Zero 2
When Elpizo launched a full frontal assault against Neo Arcadia in Mega Man Zero 2, Fefnir battled with the remaining Guardians and killed the invading force. They would have killed Elpizo too, had Zero not rescued him.

Later when Elpizo tried to infiltrate the Sanctum of Yggdrasil where the original X lay dormant, Fefnir tried to stop him in his second form that resembles a tank. However, he became infected, possibly with the Baby Elves, though the English translation of Mega Man Zero 2 makes it sound as if he was infected by some kind of virus. (Leviathan states that "It looks like Fefnir's disease infected me".) It made him incapable of thinking of anything other than fighting Zero, and helped him transform into a terrifying battle form, that was eventually defeated. Though defeated, Fefnir was not destroyed.

Mega Man Zero 3
Fefnir took part in a mission to investigate the wreckage of a crashed spaceship that contained the exiled Reploid, Omega at the beginning of Mega Man Zero 3. He was heavily damaged in the battle and did not reappear again until the final battle with Omega, only being mentioned, along with Leviathan, once in the game, in which Harpuia remarks to X that "Fefnir and Leviathan are still undergoing repairs".

According to the Rockman Zero Official Complete Works artbook, Fefnir, along with Harpuia and Leviathan, died at the end of Mega Man Zero 3 under Omega's explosion.

Mega Man ZX series
Fefnir appears in Mega Man ZX as Biometal Model F. Vent or Aile can use Model F after combining it with Model X to become Model FX. The other Guardians also appear as Biometals as well. The personality of Model F is notably similar to Fefnir's personality, even more so than with the other Biometals (When he is first acquired in Mega Man ZX, Model F excitedly asks who would be their next victim to kill). Model F is used by Atlas in Mega Man ZX Advent, however, Atlas was noticeably far less volatile and hotheaded by comparison to the original Fefnir.

Armed Phenomenon
The Four Guardians possesses a powerful alternative form called "Armed Phenomenon" which is activated by them when facing tougher enemies. When Fefnir uses his Armed Phenomenon, he appears as a red tank with several dragon-like cannon heads that attack with flames. Fefnir was the first Guardian to use his Armed Phenomenon in Mega Man Zero 2.

Other Appearances
Fefnir has his own mini-game in Mega Man Zero 3 in which he has to destroy Carryarms.

Fefnir also appears in the manga adaption of the series. He is no longer a Reploid created from X but a new type of Reploid altogether. He was the first to fight Zero and was defeated. He fights against him again in a Resistance base. When Zero was brought before Cial (Ciel's evil twin) by Harpuia, he rejected the thought, stating that he would be watching Zero. Fefnir's (along with Phantom and Leviathan's) suspicions were correct when Zero took Cial hostage. After they got Cial out of Zero's reach Fefnir and the other Generals merged to form "the ultimate Reploid" (Copy X) and was destroyed by Zero.

Mega Man Zero
Duel in the Desert
 * Cameloid
 * Carryarm
 * Carrybee
 * Flopper
 * Pantheon Hunter
 * Kerberos
 * Sand Jaws
 * Shellcrawler
 * Spiking

Mega Man Zero 2
Shuttle Factory, Chase Elpizo mission
 * Panel Cannon
 * Pantheon Hammer
 * Pantheon Launcher
 * Signaloid
 * Top Gabyoall

Temple of Flame, Neo Arcadia
 * Gli-Eye
 * Pantheon Guardian
 * Pantheon Hammer
 * Seal Cannon
 * Shaball
 * Telly Bomb
 * Top Gabyoall

Trivia

 * The new Robot Master from Mega Man 9, Magma Man, and Fefnir are both weak against the wind element, provided by Tornado Man and Sage Harpuia (two other lookalikes of each other), respectively. Both also have two cannons.
 * Like the intro boss of Mega Man Zero 2, Mega Scorpia, battling Fefnir's Armed Phenomenon also requires the player to keep up with a scroll, although it's reversed (the former chases Zero from the left, but the latter chases Zero from the right).
 * Appears to be one of the similar to the four holy beast, "Byakko".