Harvester

The Harvester is the monstrous byproduct of Amgarrak's experiments on golems. It sustains itself on the dead, whether long-deceased or freshly killed, and has been the scourge of many an expedition.

Background
The Harvester was created by accident while the smiths of Amgarrak were experimenting on Caridin's work with the hope of recreating and improving it. The smiths used dead casteless dwarves bodies instead of metal and stone, claiming that "It would be a honor for a casteless dwarf to die in such way". Tevinter mages trapped demons from The Fade in stapled flesh. The result, was the Harvester. After witnessing what their twisted creation was capable of, they were forced to trap it in a level of the Fade via the use of the Lyrium Wells and seal the thaig. Since then, people have long forgotten about both the Harvester and the thaig.

However, it seems that the Harvester is capable of manipulating the Lyrium Wells and using them to its advantage. While battling the Harvester, it shifts the Warden and his/her party through different levels of the Fade in order to become more powerful.

Involvement
The Harvester is the final boss of the Golems of Amgarrak DLC. The battle is biphasic: the first part of the battle is spent fighting the twisted flesh golem that the Harvester has amassed, and the second is where you must fight the Harvester itself. Its death triggers the destruction of the Forge within Amgarrak, and thus the thaig itself.

Trivia

 * There is also a monster called "Harvester" in Bioware's Game "Mass Effect 2", where it appears as a big flying creature on the planets Tuchanka and Tarith. However, in Mass Effect 2 it is not an enemy, as it only appears outside of the maps dropping Klixen, which are smaller enemies.