The COMPLETE Background

Big flaming spoilers below!
In order to understand where the story is now, I need to scroll the story a bit back to before even the Corwin books. I'll do this a few times probably.

Many of you know that Brand gained his amazing powers via his immersion in the Fount of Power. What you don't know is what turned mild-mannered Brand of Amber into Señ'or Psychopath.

The origin of the energy from the Fount comes ultimately from an underlying structure in shadow known in the Merlin chronicles as the Undershadow. Just as lava flows up where tectonic plates collide, energy from the Undershadow flows up where shadows collide. The Undershadow is a continuum of realities that are completely seperate from the Pattern-Logrus continuum. I explain this further in my Cosmology section. When Brand imbued himself with the energy of the Fount, he mistakenly took on creatures that are native to the Undershadow, which infected his body in parasite fashion, ate away his brain, and essentially took his place and altered his plans for his conquest of shadow.

Unfortunately, these plans went a bit awry later on when he found himself pitching headlong into the Abyss with a couple of silver arrows jutting from his throat. He was able to survive, though, and changed his guise into that of the Unicorn. Re-emerging from the Abyss with the Jewel of Judgement on his horn, he chose someone to be King that would be the easiest to manipulate: Random. At the soonest opportunity, Brand also infected Vialle, and used her influence over Random to mold him into the kind of king that Brand could control fairly easily. Meanwhile, Brand was taking the time to infect other key members of the Amber government to create a stronghold of power for himself. When he felt the time was right, he slowly began to insinuate himself into the court of Random as Vialle's onetime friend in Rebma, Spendal. From there he took a hands-on approach in the matter.

Brand's actions did not go unnoticed, however. Fiona was able to deduce who Spendal was from various small quirks the man possessed. So she formed a cabal with Bleys and Mandor to oppose the actions of Brand and his ilk. With a bit of research, they were able to reason out a possible connection between the infection, and the Fount of Power. The creatures from Undershadow seem to be undetectable by Pattern and Logrus, and only Bleys and his spikards have been able to somewhat accurately identify potential victims of the parasite. Even then, the spikards haven't proven 100% accurate, and a bit of deduction has been required to pinpoint infectees.

One thing they've made a point of doing is killing anyone they could identify as having any connection with the Fount of Power or Undershadow. So, in addition to the killing of Vialle and several Amberite officials, they've also taken on the job of killing Jasra, who controlled the Fount of Power, Julia Barnes and Marwin Morpheus, who both studied under Jasra at one point at the Fount of Power, and have made attempts on the lives of Jurt and Merlin. Jurt and Merlin were both able to escape the attack, however, and Merlin has since issued an edict against House Sawall in general and Mandor in specific. The one thing that they hadn't quite realized about all these people they assassinated due to their connection to the Fount is that none of them were infected by the parasite, as they discovered much to their chagrin after cracking open the back of the skull.

Corwin also began to suspect something was up with Random, but hadn't picked up on the idea that Spendal was really Brand. His investigations were not nearly as subtle, though, and drew the attention of the wrong people. He managed at one point to gather together Gerard, Benedict, and King Rinaldo of Kashfa to discuss the recent string of deaths. Also in attendance were Benedicts nephew, Reginald, and the Lady Seldom of House Morpheus, Marwin's sister. They didn't get much farther than comparing of notes when Random was at the door with guards demanding entrance, forcing everyone to trump out in order to avoid being caught.

A coup might have followed not long after if not for an event which threw everyone's scheming out the window: An army was detected slowly amassing and travelling through shadow. Benedict and Gerard felt obliged to stay loyal to Random for purposes of defense against this army.

The army is being led by the one-time prince of Amber, Finndo, who has long been believed to be dead. Finndo was one of the greatest pupils of Oberon and Dworkin. A master of the Pattern to rival Brand, and a master of strategy and tactics to rival Benedict. Most people thought it unlikely that he could go down in battle, and they were right. After the betrayal of Oberon, he disappeared to his personal shadow, De'alund, which consists largely of desert, with one mighty river running through it, providing a fertile strip of land in the midst of the desert. There he forged the Warped Pattern, a flawed version of Dworkin's mighty artifact, making it difficult for any but the most experienced masters of the Pattern to enter. From there he began building up his army with the aid of his generals, taken from a local race jackal-headed humanoids known as the anubi. For many centuries he planned on his revenge until he felt he was truly ready to bring his revenge down on Oberon. Unfortunately, he doesn't know that Oberon is dead.

In light of the oncoming army, Brand has decided to attempt an alliance of sorts. He is seeking out the Elder Gods that held sway before the rise of the Lords of Chaos. The Elder Gods are currently imprisoned and sleeping under the power of the Spikards, many of which have been entrusted to the Delwin and Sand. Brand's attempts to awaken the gods has gotten the attention of Delwin and Sand, but they don't feel quite capable of of taking on Brand single handedly, and so they too have formed their own cabal with a third party.

Deirdre did not die when she plummeted into the Abyss, though by all rights she should have. By sheer force of will, she managed to survive, and initiated herself into the ambient power of the Abyss, which is the opposite number to the power Brand had tapped into, the far end of the Undershadow continuum. During the years she has grown in power, and has plotted how she will gain revenge on the brother who did this to her. When the proposed alliance with Delwin and Sand to oppose Brand came, she eagerly accepted.

And so the story opens.