Once Human: How to Get Eclipse Cortex Level 3

Eclipse Cortex Lv. 3 is the top tier of the Deviant-sourced material you feed into the Stardust Filter to refine Starchrom. You can get it in three ways. It drops from tree-like Deviants in high-level pollution zones, it comes from activity rewards, and you can craft it from lower-tier cortexes. The open-world farm is the only one of these you can repeat on demand.

Quick answer: Go to the Wild Zone Pro pollution area beside the LEA Research Lab in Red Sands. Kill the tall, branch-headed Deviants there, and each one drops one Eclipse Cortex Lv. 3. About seven of them respawn over time.

Every Eclipse Cortex Lv. 3 source

The item tooltip names dungeon first-clears, Public Crisis Events, and Warband activities as official sources. The game also hands it out through several other channels.

Source	Yield	Repeatable?
Wild Zone Pro Deviants (Red Sands)	1 per kill	Yes, respawns
Dungeon first-clear	Reward	First clear only
Hard and Pro silos/bosses	1 each	Once a week
Public Crisis Events	Reward	Per event
Warband activities	Reward	Per activity
Level 40–50 missions	Reward	No
Advanced Synthesis Bench	1 per 3 Lv. 2	Yes

Elite enemies in higher-level areas can drop Lv. 1 and Lv. 2 cortexes as well. You can combine those at a synthesis bench, which makes elite routes a good source of crafting stock.

Farm Eclipse Cortex Lv. 3 in the Red Sands Wild Zone Pro

Pollution areas in Once Human contain a specific multi-limbed, tree-like Deviant. Killing it drops Eclipse Cortex Lv. 3 directly, so you skip the crafting chain entirely. The Red Sands zone works well because it packs several of these Deviants into one field.

Open the world map and go to the Red Sands biome. Find the LEA Research Lab, which has a Recommended Level: 60. Its teleportation point may still be locked, so plan to travel there on foot or by vehicle.

Select the pollution area right next to the lab. The popup should read Wild Zone Pro and show a tree icon under Current Deviant Influence. That tree icon tells you the zone holds the cortex-dropping Deviant.

Map Location & Wild Zone — The Wild Zone Pro area beside the LEA Research Lab in Red Sands. Look for the tree icon in its popup. Shown at 00:25 in HeRo Survival Guides’s video. Image: Starry Studio

Place a map marker on the zone and travel into it. A red haze around the edges of your screen means you are inside the pollution area.

Pollution Area Method — Inside the Red Sands pollution field, where the cortex-dropping Deviants roam. Shown at 00:07 in HeRo Survival Guides’s video. Image: Starry Studio

Scan the landscape for a tall Deviant with a branching, tree-like head. A scoped weapon makes it easier to spot and target the Deviant from a distance before you engage.

Kill the Deviant and pick up the loot it leaves behind. Each kill gives one Eclipse Cortex Lv. 3, three Acid, character XP, and a small amount of Battle Pass XP.

Locating and Defeating the Deviant — The branch-headed Deviant that drops Eclipse Cortex Lv. 3, lined up through a scope. Shown at 00:44 in HeRo Survival Guides’s video. Image: Starry Studio

Move on to the next Deviant in the field. The zone has roughly seven spawns, and they come back after a short wait, so you can loop the area for steady drops.

Wild Zone Pro increases mutations in animals and plants and suppresses long-range responses. Expect the zone itself to behave differently from normal open-world areas.

Craft Eclipse Cortex Lv. 3 from Lv. 2

At the Advanced Synthesis Bench, combine 3 Eclipse Cortex Lv. 2 to produce one Eclipse Cortex Lv. 3. The process lasts 5 to 10 seconds, with the exact time varying by scenario. First, purchase the Advanced Synthesis Bench memetic in the Cradle’s Crafting page to unlock the formula; its price varies by scenario.

Scenario	Memetic node	Cost
Endless Dream, Evolution’s Call, Manibus, Prismverse’s Clash	05 Enlightenment	7 cipher, 2000 Energy Link
The Way of Winter	05 Entropy	3 cipher, 2000 Energy Link
Survive, Capture, Preserve	05 Enlightenment	7 cipher, 2000 Energy Link

In Survive, Capture, Preserve, the node is only available after you reach Symbiosis level VIII. Combining lower tiers upward pays off. A Lv. 3 cortex produces more Starchrom in the Stardust Filter than a Lv. 1 or Lv. 2.

Confirm you have Eclipse Cortex Lv. 3

A successful pickup shows the loot notification Eclipse Cortex Lv. 3 (+1). To double-check, open your backpack and find the item in the Materials category. Its tooltip describes it as a substance inside Deviants’ bodies that holds impure Stardust energy, and it lists the dungeon, Public Crisis Event, and Warband reward sources.

Farming & Alternative Acquisition Methods — The Eclipse Cortex Lv. 3 tooltip in the backpack, confirming the drop and listing its official sources. Shown at 01:09 in HeRo Survival Guides’s video. Image: Starry Studio

The tooltip also marks the item as Unable to deposit, so it stays in your backpack instead of going into storage. You also cannot sell it to merchants, list it on the Harvester’s Market, or trade it to other players. Every cortex you hold has to come from your own farming, rewards, or crafting, and its only destination is your Stardust Filter.