Uber Venarius Farm

Overview

Uber Venarius is the hardest version of the Cortex fight, opened in The Unleashed Cortex at area level 85. You never fight Venarius himself. He summons four Synthesis bosses in sequence, and killing the last one drops one guaranteed synthesised unique from a pool of five. One of those five is worth far more than the other four put together, so this is a strategy you run for a single item.

Setup

• Four Synthesising Fragments. They are used to open one instance of The Unleashed Cortex and are consumed on use. Nothing else is spent per run.
• About three minutes per run. That covers the whole loop end to end, not just the fight: opening the instance, clearing all four phases, and picking up loot. It assumes a good build clearing it cleanly, so treat it as a target rather than a floor.

The Encounter

• Four phases in a row. Fractal Gargantuan, then Synthete Masterpiece, then Fractal Titan, then Synthete Nightmare. There is a short intermission after the second one where weaker monsters pour out of four portals.
• Everything takes 70% less damage. This is the main reason the uber version is slow. Bring real single-target damage or the fight drags long past three minutes.
• An extra unique Synthete spawns in every phase. These are the four Synthesis map bosses, and they stay alive between stages if you kill the main boss first. You can end up fighting three things at once.
• The floor kills you slowly. Void Pits stack a physical degen and cut your action speed, and Energy Pylons zap anything that touches them. In the uber version pylons appear in all four phases, not just the last two. Keep moving and touch a pylon a second time to switch it off.
• Two attacks you must dodge, not tank. The Wormhole Slam pulls you in front of the boss for a heavy cone hit, and the Laser Cage closes a ring of lasers on the arena centre. Both need a movement skill ready.
• Do not leave the zone after the last kill. Venarius drops loot on a delayed animation. Leaving early can lose the drop entirely.

How These Numbers Were Calculated

These figures are modelled, not measured. Nobody ran 100 Uber Cortex and recorded what fell out.

• The method. A synthetic sample of 100 kills built from the published drop rates. A 5% chance is counted five times across the sample, a guaranteed drop 100 times. Expenses are one run's four fragments multiplied by the same 100 runs. The hourly figure is the net total spread over five hours, which is 100 runs at the three minutes per run given above.
• The rates are estimates. The wiki's own table is crowdsourced and says so. The uber numbers come from about 365 kills recorded across versions 3.25 to 3.27 and about 315 more in 3.28. That is a decent sample for the guaranteed pool and a thin one for the rare rows, so real results over a short run of kills will differ from the model.
• Imperfect Memories is a guess. Its rate is listed as under 0.5% with a note asking for confirmation. It is counted at that ceiling here, which nudges the total up slightly.

Almost all of the modelled profit sits in one item. Rational Doctrine is 5% of the guaranteed unique pool and roughly 97% of the profit, which means the other four uniques, the Reliquary Key and everything else combined barely cover a tenth of your fragment cost. You will average one Rational Doctrine every twenty kills, and going forty or fifty kills without one is normal variance, not a sign the strategy is broken. It also means the whole thing moves with that single item's price.