I didn’t think I needed to, really, mention that all of these observations are rife with my UPG, but just in case …they are all chock full of my UPG.
Why did Odin choose a blood bond rather than a marriage with Loki? I suppose the argument could be made that marriage between two men wasn’t done in Their culture or rather the filter of the culture we know Them best from, the Nordic folks, but blood bonding was the acceptable equivalent to anchor Loki solidly in Odin’s family. I think the choice was more deliberate than a default. Odin could have chosen to do any number of other things, a good few I probably would never think of, but I don’t think any other bonding but one of blood would have satisfied their relationship as it stood. Even had Loki been a woman, a Goddess rather than a God, and a marriage had ensued I believe a blood bond would have still been exchanged. The essence of Odin needed Loki-his changeability and adaptability only augment Odin’s own being. A large part of the essence of Loki is Wit and Limits and a sound ruler/father/patriarch can’t afford to be bogged down without it. All that being said, in many ways the merging of their essence was a happy accident based on Their shared Passion and Love. They satisfied a need in one another and brought each other into balance.
Odin and Loki would not be the Gods we know today without the Other. Loki keeps Odin modern and Odin occasionally yanks Loki out of trouble and to His side (or to His side to solve trouble). Also, as a God who walks the road in between and who pushes boundaries Loki can keep Odin with all of his knowledge on this side of sanity. Knowing too much is never good for anyone. He can help Odin set limits of what is and isn’t okay to do based on His knowledge.
Blood Bond vs. Marriage
A marriage is more on the lines of a contract and can turn into one partner, stronger in some way, overwhelming the other (mentally, physically, financially, status wise). The nature of modern marriage has it predisposed to be romantic, but historically it was more contractual with the hopes that a good partnership would be formed from the arrangements.
A blood bond is by its very nature more about sharing-shared life, shared bond, shared essence. Once can be forced into marriage, but this type of bond cannot form at all without the direct desire of the participants at the time of inception and would be far more difficult to break, if it can be broken at all.
Magic is involved in a blood bond-water, earth, fire, air, and spirit all find a place in such a bond imbuing it with power. Magic can be woven into a marriage bond, but the blood bond has it naturally.
Earth: The bones and body through which the blood flows.
Water: The blood.
Air: The breath is in the blood and also animates the body, as well as carrying promises and oaths.
Fire: Is the Passion and the heat of life.
Spirit: The soul and energy merging which occurs.