Forgotten Tower

"And so it came to pass that the Countess, who once bathed in the rejuvenating blood of a hundred virgins, was buried alive...And her castle in which so many cruel deeds took place fell rapidly into ruin. Rising over the buried dungeons in that god-forsaken wilderness, a solitary tower, like some monument to Evil, is all that remains."

- Writing on the tower

The Forgotten Tower is a structure that resides within the Black Marsh of Khanduras.

Lore
"A blight seeps from the Forgotten Tower. At its root lies a woman in a pool of stolen blood. Around her neck, a red stone pulses with a power older than the world itself."

- Hemlir

Early History
The Forgotten Tower is all that remains of a castle once inhabited by The Countess. For her cruel deeds, she was buried alive, and her castle fell into ruin. By the year 1264, all that remained of the castle was a single solitary tower, looming over the wilderness like a monument to evil. An epic poem was written about the tower, about how much sorrow one could stand there. The tower was not only dangerous due to its state of disrepair; once inside, many succumbed to a vile miasma. Reportedly, several Sisters of the Sightless Eye perished once a staircase collapsed on them. Through means unknown, the Countess emerged, but was slain by a group of heroes inside her tower, and its riches were plundered.

The Bloodsworn
"The strongest of the Bloodsworn rogues will be found inside the Forgotten Tower, protecting their mistress. To break their ranks, we must defeat these rogues on their own ground."

- A Westmarch bounty

Six years later, the Countess returned once again, and resided within the tower. Dwelling within a pool of blood, fed to her by the Blood Rose. Because of this, parts of the tower became overgrown with Dark Creeper vines.

The tower became the headquarters of the Bloodsworn. The strongest of their number were stationed in the tower, acting as bodyguards to the Countess. The Sisterhood of the Sightless Eye launched an assault against the tower, but the attack faltered, such was the ferocity of the Bloodsworn's defense. Another group of heroes came to the tower, slaying any Bloodsworn hat got in their way, though the Bloodsworn engaged in a blood ritual that the hero(es) failed to stop, which resulted in the resurrection of the Countess. However, the Countess was slain after a long battle.

Diablo II
The Forgotten Tower appears as a zone in of Diablo II. It lies in the Black Marsh, which connects to the Tower Cellar. Technically the Forgotten Tower only refers to the small area located directly beneath the tower ruins; there are stairs leading up towards the Black Marsh and down into the cellars. The quest is given by the Moldy Tome found in the Stony Field.

Diablo Immortal
The Forgotten Tower is revisited in Diablo Immortal as a dungeon. The Countess is once again confronted. It differs from its predecessor in that its layout is more open.

Trivia

 * The tower was to be visited by Jacob in the Sword of Justice comic series. However, the respective plotline was canceled.