Fenrir

Fenrir (フェンリル) is a character introduced in Shinyaku Toaru Majutsu no Index. A member of GREMLIN, he is deployed to Alaska during GREMLIN's attack on Tokyo.

Etymology
In Norse mythology, is a monstrous wolf. Fenrir is the father of the wolves Sköll and Hati Hróðvitnisson, is a son of Loki, and is foretold to kill the god Odin during the events of Ragnarök, but will in turn be killed by Odin's son Víðarr.

Appearance
He was only described as being a young man.

Magic God Othinus Arc
He appears in Alaska to take out a NORAD base there as a means of sealing off the alliance's intelligence network. When he reaches where the base's parabolic antennae arrays are stored, he is ambushed by Oriana Thomson, whom he effortlessly blocks with his magic. After the explanation of his distortion spell, she commented that she would just have to use the countermeasures she developed if she should have to fight Kamijou Touma again. Realizing she's comparing his power to the Imagine Breaker he retorts that he doesn't completely annihilate the occult, just simply have the magic be "swept away", and can not take the role of being a reference point for the world.

VS the World
He later appears at Egeskov Castle with Hel, Jörmungandr and other members of GREMLIN, waiting for Othinus to arrive and take revenge for her abandonment of them. When Jörmungandr jokes that he finds it amusing that the Anti-GREMLIN Alliance hasn't realized what her destination was, Fenrir comments that he didn't leak the information for fun allowing them to be there first. They then notice the crowd part to reveal the arrival of Thor who suggests that they decide on a representative for when Othinus arrives, his idea on selection being a battle royal of the members present. He is likely among the pile of scattered bodies when Touma and Othinus arrive at the castle.

Abilities
Fenrir is able to distort the space around him as explained by Idol Theory. Taking the story of how the gods had feared Fenrir because of how he would devour Odin during the final battle of Ragnarök, and so they bound him and stabbed a sword into his mouth through the lower jaw so he could not close his mouth. When they had, the drool that had flowed from Fenrir’s giant maw had created a large river.

He thus uses something similar to Feng shui where the existence of mountains and rivers changes the flow of energy through ley lines and the like. In this case, he can create a ‘ditch’ that draws in the surrounding energy by creating a new mountain or river. The spell creates a number of black cracks, forcibly swallows up the magic power that constructed magic and swept it away. The phenomena that appears after using it appears as "cracks" in space.

This magic of his to "swallow up" magic into the "ditch" is described as being "bitten" into. A further reference to this metaphor is Fenrir saying that he doesn't need his canine teeth, and just needs to release his central incisors or lateral incisors to tear Oriana apart, which implies that there is more to his magic than having other magic be swept away.

Quotes

 * (To Oriana, from NT8) "I don’t even need my canine teeth for this. If I release just my central incisors or lateral incisors, I can tear you to pieces right away."