Becoming the Thieves Guild Master
Once you have completed all of the reputation quests, and "Darkness Returns", you are ready to become the new Guild Master.
When you enter the Cistern, a crowd will be gathered, there is a short ceremony, during which you are named Guild Master.
Heavily modded game ahead, also, due to some mods being installed and updated middle playthrough, there are a couple of inconsistencies on some objects (floating or out of place).
The ENB needs a tune-up too since I messed too much with the original values, I´ll try to do better next time... maybe...