Kvasir (pronounced “KVAHSS-ir”) is a being who was created by the Aesir and Vanir gods and goddesses at the conclusion of the Aesir-Vanir War.
The war had ended with a truce. In the tale of the Mead of Poetry, whose storyline picks up where that of the Aesir-Vanir War leaves off, the deities sealed their peace treaty by coming together to produce an alcoholic drink by an ancient, communal method: everyone in the group chewed berries and spat out the resulting mush into a single vat. This liquid was then fermented. In this particular instance, the fermented liquid became the god Kvasir, whose name is surely related to Norwegian kvase and Russian kvas, both of which mean “fermented berry juice.”
Kvasir was the wisest of all beings. There was no question for which he did not have a ready and satisfying answer. He took up the life of a wanderer, dispensing his wisdom to all whom he met along the road. When he came to the house of two dwarves, Fjalar (“Deceiver”) and Galar (“Screamer”), they killed him and drained his blood into three containers. They told the gods that Kvasir had suffocated from an excess of wisdom. The two dwarves then brewed mead by mixing Kvasir’s blood with honey – the Mead of Poetry.
The story of the Mead of Poetry comes from the medieval Icelandic historian Snorri Sturluson, whose works can’t necessarily be taken at face value. However, we have good reasons for accepting this story as authentic, at least in its general outline. In Old Norse poetry, “Kvasir’s blood” (Kvasis dreyra) was an established kenning for poetry. There’s also a mythological narrative from India that closely resembles Snorri’s account of the Mead of Poetry. Both stories probably grew out of a common, and much older, Indo-European myth.
However, in an excellent example of why it’s a bad idea to accept Snorri uncritically, Snorri contradicts this story in his description of the Aesir-Vanir War itself. There, he claims that Kvasir was a Vanir god who went to live with the Aesir when the two tribes exchanged hostages long before the peace treaty was established. Of course, if Kvasir was only created after the war had ended, it would have been impossible for him to have been alive during the war. Since Snorri’s account of the Mead of Poetry is corroborated by outside evidence and his account of the Aesir-Vanir war is not, the most reasonable interpretation is that his account of the Aesir-Vanir War is wrong, at least on this point.
There’s no evidence that there was ever a cult of Kvasir. He seems to have been solely a literary figure who epitomized the qualities of the Mead of Poetry. Since the Mead of Poetry became the exclusive property of Odin shortly after its production, it should come as no surprise that the defining characteristics of Kvasir’s personality are all attributes that are more commonly and more powerfully associated with Odin himself.