The Courts of Chaos by Roger Zelazny

This is the grand finale of the first act of the sweeping Amber series. King Oberon has returned to Amber, and has taken over in his usual high-handed fashion, leaving his heirs reeling emotionally. He reclaims the Jewel of Judgement, and is going to use it to attempt to repair the Pattern which was damaged by Brand. The effort may or may not succeed, but it will surely claim his life, either way. He tells Corwin he will name him as heir, but after all which has gone on, Corwin no longer desires it; feeling it was merely a prize in his sibling rivalry with Eric, after all.

Oberon sends Corwin on a mission to ride as far and fast as he can, ahead of the disruption that will be caused by his Pattern restoration attempt, and to receive the Jewel at some point along the way, then bearing it on to the Courts of Chaos, where Corwin can use it to direct the storm to spare the Amberites there. Benedict has been directed by Oberon to gather an army in Shadow and take them to battle with the armies of Chaos, and the rest of the brothers and sisters also join in.

So Corwin begins a strange and metaphorical journey to the Courts, meeting some interesting semi-legendary creatures along the way. Zelazny gets very descriptive and subjective for the middle portion of the book, which breaks from the pace he's set in the early series. Once Corwin reaches the Courts, however, the action picks back up again, and the final confrontation between Amber and Chaos, the fate of Brand, and the disposition of the crown provide a bittersweet and mostly satisfying conclusion to the saga.