At the feet of the father of the gods lie two wolves: Geri and Freki – both names mean „the greedy one". In the hall of Valhalla, Odin gives them every piece of meat from his table and lives on wine alone.
Odin is surrounded by animals that mirror his nature: the ravens Hugin and Munin („thought" and „memory") bring him news from all the world, the eight-legged steed Sleipnir bears him between the worlds – and the wolves Geri and Freki attend him as lord of the battlefield. For wolf and raven are the beasts that follow the slain; where Odin holds sway, they are never far.
“Geri and Freki the war-glad Father of Hosts feeds; / but on wine alone the weapon-splendid Odin lives forever.”— after Grímnismál 19, Karl Simrock (public domain)
The wolf is Odin’s beast because Odin is the god of battle and the dead – and it is wolf and raven that follow the slain. In Old Norse as in Old English poetry, „wolf, raven and eagle" form the fixed beasts of battle that precede the fight. Odin’s wildest warriors, the úlfheðnar („wolf-coats"), wore wolf-skins and fought in ecstatic frenzy – wolves in human shape.
So Geri and Freki are more than pets at a throne: they are an emblem of the war-god’s double face, embodying wisdom and havoc at once. Whoever tames them commands the beast within.
Odin · Valhalla · The Einherjar · The Fenris-wolf.
Grímnismál 19 (Poetic Edda); Snorri, Gylfaginning 38. Rudolf Simek, Dictionary of Northern Mythology.