Norse God of mischief if I recall.
Loki wasn't a God. He was a halfling.
His father was Farbauti, a name translated by at least one source as 'Anger Striker'
This places his father as a Giant, the mortal enemies of the Aesir and especially Thor.
https://en.wikipedia.org/wiki/F%C3%A1rbautiHis mother was Laufey, or Nal, a minor character in Asgard mentioned in only one of the thular, or lists.
Odin swore blood brotherhood with Loki in an attempt to stave off future trouble with Loki, not something the Father of the Gods would do with his son.
http://burningblood.livejournal.com/10342.htmlThe concept of Odin and Loki being blood brothers usually gets referred back to two kennings for Loki given in the Skáldskaparmál ("bróður Býleists ok Helblinda" with the latter demonstrated and the former theorised to be bynames of the Old Man), plus verse 9 of Lokasenna.
9. Loki kvað:
"Mantu þat, Óðinn,
er vit í árdaga
blendum blóði saman?
Ölvi bergja
lézktu eigi mundu,
nema okkr væri báðum borit."
Auden and Taylor translate L9 thus:
"Remember, Odin, in the olden days
What blood-brothers we were:
You would never have dreamed of drinking ale
Unless it was brought for us both."
Thorpe offers this interpretation:
"Odin! dost thou remember
when we in early days
blended our blood together?
When to taste beer
thou didst constantly refuse,
unless to both ´twas offered?"
This is Bellows' take:
"Remember, Othin, | in olden days
That we both our blood have mixed;
Then didst thou promise | no ale to pour,
Unless it were brought for us both."
Pretty much all the translations agree on that one: At some time in the past, Loki and Odin mingled their blood ritually; blood-brotherhood is only mentioned specifically by Auden and Taylor, but some kind of kinship oath is most definately implied. During this oath, Odin gave some undertaking never to drink unless drink were also offered to Loki. Given the high status of alcohol and the sharing of drink in the culture of the time this itself is quite a biggie. Alcohol was the preferred entheogen of the heathen, the very blood of a God. Communal drinking is a major feature of many important rites, and in some cases seems to serve to place the compotators half-in-half-out of the world of the spirits in a very literal sense.
(Incidentally, here is what I got when I had a go at it:
Loki quoth:
"Remember you that--Odin!--it was we (who) in days of old
blended our blood together?
Ale-tasting permit not, would you
Save us it was for both borne")
However, Loki is nowhere else referred to as Odin's "blood-brother" and there are no accounts of such a rite (that I know of). This has lead some to suggest that the whole blood-brother thing is an attempt to make Odin look bad by having Him chum up to this ethically divergent Jötun (with the "brother of Helblindi" bit glossed over as Odin happening to share a kenning with some unknown Jötun), and others to suggest that Loki is Odin's brother in the more usual sense, and the blood-brother thing is an attempt to make Loki look bad by making His relation to Odin more uncertain.
I'm not convinced by either. For one thing, both Odin and Loki's parents are named elsewhere in lore, and those names differ in all cases. To the best of my knowledge, you never see Bor referred to as Loki's father, or Laufey referred to as Odin's mother. For another thing, most people seem to skip over stanza 16, which also supports the adopted-kin angle. Here, Idunna is taking her turn at cooling things out by trying to placate Her husband Bragi:
16. Iðunn kvað:
"Bið ek þik, Bragi,
barna sifjar duga
ok allra óskmaga,
at þú Loka
kveðir-a lastastöfum
Ægis höllu í."
Auden and Taylor render this as:
Idun:
"Think, Bragi, I beg, of our children,
Of all our kith and kin
And do not bandy abuse with Loki
In Aegir's banquet hall"
--suggesting that Idunna fears harm to her family from Loki if Bragi yanks Loki's chain. But Bellows gives the verse as:
"Well, prithee, Bragi, | his kinship weigh,
Since chosen as wish-son he was;
And speak not to Loki | such words of spite
Here within Ægir's hall."
--which puts a rather different complexion on things. Here the term "wish-son" (adopted son) is used instead of "blood-brother." Similarly, Thorpe gives:
"I pray thee, Bragi!
let avail the bond of children,
and of all adopted sons,
and to Loki speak not
in reproachful words,
in Ægir´s hall."
When I had a word-by-word go at it with various online dictionaries, it seemed like Thorpe and Bellowes were closer to the mark. Here's what I got:
Idunn quoth: "Beg I you, Bragi! Kinship support, and all wish-kin;
To you Loki [may] utter abuse (against us) Aegir's hall within."
The interesting word here is "óskmaga," which gives "wish-kin"--adopted kin.
These days of course it is quite normal for modern writers to pull kennings, associations, and indeed whole swathes of counterfeit "knowledge" out of their various orifices and chuck them around as if they were not only supportable from the lore but self-evident and universally accepted ("...and so we can see that Loki--who is really a masculinisation of the Morrigan--stole the Brisingamen, which being a vaginal symbol is actually the Holy Grail--from the phallocentric forces of Odin, who is really the Cyclops from the Odyssey, thus proving that Odysseus is really the Great Goddess in Her aspect of a blah blah blah..." well, you know how they do go on). However, when Lokasenna was composed and set down you couldn't get away with that sort of thing. You had to be on the same page as your audience or they wouldn't put up with you. You used kennings that people would understand (maybe with a bit of unpacking), you didn't just make up any old rubbish and hope that people would be too credulous or ignorant to spot it. The intended audience for Lokasenna must therefore have been assumed to understand and accept Loki and Odin as having some kind of ritual adoptive kinship.
Although only L9 actually talks about mingling blood, the reference to "óskmaga" in L16 seems to support the idea of some kind of adoptive kinship, with the sharing of ale and the Gods' forebearance in the face of Loki's ill behaviour suggesting that this was a big, serious ritual commitment, one which even Odin couldn't simply set aside.
It is true that we're still left with a relationship only alluded to in the Eddas, but it seems odd to dismiss a relationship alluded to in two verses of a key poem.