Blood-Oath Celebration

The Blood-Oath Celebration, called the Agaetí Blödhren in the Ancient Language, was a centennial Elvish ceremony.

Purpose

The Blood-Oath Celebration commemorated the pact formed between the elves and dragons at the end of Du Fyrn Skulblaka, or "The Dragon War".

This was a spell that took nine years to create. Queen Tarmunora and her spellcasters gathered at Ilirea, along with a white dragon, whose name could not be spoken in any language, chosen to represent the entire dragon race. Together, they melded the souls of elves and dragons, giving the elves immortality and dragon magic. In return, the dragons received language and civilization (although to what extent is unclear, seeing as the dragons had no known cities) and they vowed that there would never be another dragon war. Layered within these enchantments were the mechanisms needed to bind a dragon to its Rider.

Ceremonies

The Elves crafted different works of art or magic to be shown at the celebration. In Eldest, Eragon, Arya and Islanzadí presented poems, Orik a wooden pyramid of interlocking pieces, Oromis a painted scroll, Glaedr a carved wooden likeness of Ellesméra and Saphira a piece of rock she had sculpted into shapes by licking the molten rock. There was much singing and dancing and the elves often chanted magic spells. The elves celebrated in frenzy and madness, seeming to temporarily lose their sanity. Eragon was almost lost in the enchantments, as if he had been drinking heavily.

During the third day of the celebration, two elves (the Caretakers, Iduna and Nëya), dancers with dragon tattoos on their bodies, danced and chanted as they spun in circles around each other, at first slowly, but then very fast. At the end of the dance, the dragon tattoo broke free of the twins' skin.

Purpose in Eldest

During the Agaetí Blödhren, the living consciousness bound into the dragon tattoo on the Caretakers' skin approached Eragon and touched Eragon's gedwëy ignasia, causing his slow transformation into becoming more elf-like because of his connection to Saphira to happen instantly.

All of his blemishes and scars disappeared: his facial features became more angled and his ears more tapered, his senses were enhanced and he became faster and stronger, like an elf. His prowess in magic increased to great heights. But the most important part of Eragon's metamorphosis was the healing of the scar on his back from Durza, which had been causing him unbearable pain if he strained or over-exerted himself. When he faced Vanir in a dueling practice, Eragon outmatched the elf and won his respect.

Deus Ex Machina

Some critics say that the transformation effected upon Eragon during the Blood-Oath Ceremony is an example of deus ex machina, a literary device where the author chooses to give a character a short-cut out of a seemingly impossible situation: in this case, fighting Galbatorix with a debilitating scar and merely human abilities.

Others have praised the transformation, saying that it is only after Eragon learns the meaning of pain and grows wise through months of suffering that he is liberated. Oromis mentioned earlier in Eldest that he would eventually teach Eragon spells to remove his pain at a point in his training anyway.