Garmr

Garmr is the legendary Hellhound guardian of Hel in Norse mythology and the familiar of Arthur Pendragon.

Appearance
Garmr initially took the form of an small pup-sized wolf with blueish-gray fur and mechanical hindlegs, but will eventually change in size and shape along with Arthur's growth.

By Volume 17, Garmr grew to around seven meters, being large enough to allow all three of Mina, Elaine and Waltraute to ride on it around the battlefield.

In True Volume 5, though only temporary, Garmr grew to about twelve meters tall and was given an extremely mechanized design.

Personality
While not much of Garmr's personality has been shown, it is stated by Fenrir that Garmr is both self-awareness and possesses human-like intelligence, though his way of thought was different than a normal human's, similar to Fenrir.

History
Garmr is one of the Hellhound Jötunn pups that helped guard Hel in Norse Mythology. While their numbers are large, apparently very few ever last to adulthood.

Volume 13
In the Extra Life of Volume 13, "The Worries of the Next Heiress" (which takes place after Volume 12), Arthur was given a familiar, the mechanical Jötunn Hellhound pup Garmr, by Surtr Sekund along with Ryuuteimaru for Hinami. Although it is only the size of a small five-meter size pup, according to MacGregor Mathers, it will continue to grow and evolve into different forms by using the aura and imagination of its master as its source.

Volume 14
It was briefly mentioned by Arthur when he was discussing familiars with Elaine and Hinami. He states that he made a master and servant relationship with his familiar, Garmr, which shows some compatibility between the two.

Garmr later makes an appearance during the confrontation with the Stray Magicians from the Chaos Insurgency when Arthur summons it as means of transportation as his Devil and Seraph wings were rendered inactive.

Volume 17
In Volume 17, Garmr was summoned to support Eden against the battle with Qlippoth. Its size has changed from the size of a small pup to a slightly mechanised wolf. Garmr was used to transport Mina and Elaine, with Waltraute guarding her, from one place to another through the battlefield to help the wounded.

True Volume 5
Garmr reappeared in True Volume 5, who has entered an a cocoon state and was brought to Hell in the Grigori’s establishment to be analyzed by Bonnibell Belial and Shemhazai, with the assistance of Seekvaira Agares.

Powers & Abilities
Growth: Garmr will grow and evolve into different forms by using the aura and imagination of its master as its source.

Immense Strength: Despite its small size, it can still fly while carrying its master. Garmr states that it has amazing horsepower and strength, which was demonstrated when it was able to carry him during the battle with the Stray Magicians.

God-Killing Fangs:

Immense Speed: Garmr is able to move at god-like speeds, making him extremely dangerous when attacking with his fangs and claws.

Enhanced Senses:

Flight: Garmr is able to hover and levitate himself.

In Apocrypha AnswerArms (AxA)
By using Scarlet Grand's power, Garmr can transform into a powerful wolf-based mobile armor base that Arthur can pilot. The power that Garmr has in this form is so great that it overwhelmed Tartarus, a Primordial God in Greek mythology. It has the power to destroy the entire world with it's destructive power. Because of the weapons that was installed in it, Garmr gains new abilities in this form.
 * Revelation Barrier: Creates a stronger barrier around the body and is powerful enough to withstand attacks from gods such as Tartarus.
 * Revelation Blade: With four arms of his Apocrypha AnswerArms form, each of the arms carries aura blades known as Apocalypse Caledfwlchs which can easily cut through anything like Tartarus' tentacles.
 * Revelation All-Range L-I-Blaster: Similar to Cardinal Crimson Incursio and Diabolus Dragon Beast Lilith, Apocrypha AnswerArms has many cannons to fire powerful blast of auras that can destroy Tartarus’ magic barriers like paper and destroys almost half of his body, even as Arthur held back his power. The blast of destructive energy is so powerful it can alter the environment and is strong enough to destroy the artificial space created by Paradise Lost and Innovate Clear Edge. Arthur states that the blast is comparable to several Longineus Infinity Blaster's blast attacks combined.