Fenrir

Fenrir is a Demon of Niflheim, the eldest of Loki's 'Siblings of Catastrophe' and elder brother of Jormungandr and Hel. He incarnates as a wolf whose size and appearance vary with the situation; in his original form he is a gigantic, ferocious wolf able to devour a grown human whole.

After descending to the lower floors to aid Cha Yeon-woo, he behaves like a dog seeking his master's affection and develops a fixation on Yeon-woo (amplified by the Soulstone of Lust). He forms an unlikely friendship with Agares. His speech is mostly barking, which many can surprisingly understand, though he can speak normally if he wishes. Like his sister Hel and father Loki, he loves being the center of attention.