Thrall Room

The Thrall Room is an encounter room in the Shattered Throne dungeon, reached just after the first encounter, directly after the rafters combat encounter. It spawns a steady stream of Shadow Thrall that are easy to kill, which makes it a popular farming spot for Corrupted Key Codes.

Farming

Keys drop from enemies as small blue motes that must be picked up, and they stack to five. Drops are small-chance and random, so a run can take a long time. The most-cited guide on this is from 2021, so current drop rates and farming spots may differ.