Corvus

"This place is a dump. They should dismiss the chambermaid."

- Shanar

Corvus is a ruined city that lies beneath the Blood Marsh.

Early History
Corvus was one of the first cities of Sanctuary, established by the nephalem, and one of Sanctuary's greatest civilizations. According to legend, it was primarily a place of peace and shelter, shielding them from powerful spells of some kind. Passages in the Books of Kalan indicate that the city was built by Daedessa the Builder. Lidar the Noble infused the city with some form of magic that could ward off trespassing angels and demons. Cullen suspected that the power that shielded Corvus was tied to the creation of Sanctuary itself, and the interaction between the physical and ethereal planes. He further suspected that the city existed within its own realm.

After Inarius altered the Worldstone to stymie the nephalem's abilities, the nephalem became mortal, and forgot their past heritage. Thus Corvus was forgotten and left to come to ruin. Powerful defenses left behind by its nephalem inhabitants deterred most adventurers from finding the city.

Rakkis
"Daoril is dead, burned away from the inside out. But we are beyond the door now. I have learned a valuable lesson from many foiled attempts: only a true nephalem shall possess the key to open it."

- Korsikk

Millennia later, Rakkis, having heard of the existance of the nephalem and Corvus, established Westmarch near where Corvus was said to lie. Obsessed with the nephalem and the power they held, it was his ambition to locate Corvus. He succeeded in locating the city, and took the Wolf of Corvus as the sigil for his new kingdom. The lure of potential immortality convinced Rakkis that he might even be nephalem himself, though after many fruitless years of wandering the crumbling remnants of the city, his only consolation was to have his remains entombed within.

It is said that at the age of 100, Rakkis died peacefully in his sleep. In his final years, Rakkis requested that he be buried among the ruins of the lost city. This was apparently granted, and Rakkis was entombed in the heart of Corvus.

Recent History
The destruction of the Worldstone did not appear to weaken the magic guarding Corvus, potentially due to its 'pocket realm' magic.

Long after the death of Rakkis, the Black Soulstone was hidden in Corvus by Tyrael and the reformed Horadrim. However, it was taken by Malthael. The ruins were later entered by Adria, as she searched for Malthael's whereabouts. She was tracked down by the Nephalem and killed, but not before discovering that Malthael was residing in the Pandemonium Fortress.

In-game
Corvus is explored in of Diablo III. It is divided into the Ruins of Corvus and the Great Hall.

The Passage to Corvus, Nephalem Proving Grounds and Unearthed Ruins are, apparently, part of the city as well.