Mass Effect 2: Codex Mass Effect 2 guide, walkthrough
Last update: 02 June 2021
The table seen below contains a list of new codex entries which may be added to your journal during the game. You should know that all the codex entries from Mass Effect 1 are also available in the sequel and you can read all of them as soon as you've started a new game.
Important! In some rare cases you may unlock an entry by doing something slightly different (for example, by fighting a certain group of mercenaries for the first time in a different area) so you should treat the hints provided below only as sure bets how to unlock them.
Entry name | Moment when it becomes unlocked |
A-61 Mantis gunship | Talk to Sergeant Cathka (Omega - Archangel's base). |
Aeia | Take your first trip to the planet Aeia. |
Aliens: Praetorians | Win a battle with the first Praetorian during the Horizon mission (one of the main quests of the game). |
Argus planet scan technology | Develop Advanced mineral scanner technology. |
Asari: Ardat-Yakshi | Start Samara's personal quest. |
Asari: Justicars | Talk to Samara on board of the Normandy. |
Ascension | Purchase this magazine from the Zakera Cafe store (Citadel). |
Blue Suns mercenaries: Full history | Install Zaeed DLC, start Zaeed's personal quest and meet Vido for the first time. |
Cerberus | Meet Jacob during the prologue. |
Cerberus: The Illusive Man | Meet The Illusive Man during the prologue. |
Collector particle beam | Find the particle beam cannon (heavy weapon) during the Horizon mission (one of the main quests of the game). |
Collectors | Finish the prologue. |
Collectors: Collector general | Talk to a Mechanic during the Horizon mission (one of the main quests of the game). |
Computers: Haptic adpative interface | Examine the controls on Normandy's second deck. |
Drell: Biology | Talk to Thane on board of the Normandy. |
Drell: Culture | Talk to Thane on board of the Normandy. |
Fornax | Purchase this magazine from the Omega market store (Omega). |
Freedom's Progress | Talk to The Illusive Man for the first time during the prologue. |
Geth: Heretics | Recruit Legion to join your crew (activate him after completing an important part of The Reaper IFF quest). |
Haestrom | Find yourself on the surface of the planet Haestrom (one of the main quests of the game). |
Helios thruster module | Develop Extended fuel cells technology. |
Horizon | Find yourself on the surface of the planet Horizon (one of the main quests of the game). |
Husks: Scions | Defeat the first scion during the Horizon mission (one of the main quests of the game). |
Illium | Take your first trip to the planet Illium (Nos Astra city). |
Korlus | Find yourself on the surface of the planet Korlus (one of the main quests of the game). |
Krogan: Blood rage | Talk to a Krogan during the exploration of the Blue Suns facility on the planet Korlus. |
M-451 Firestorm | Install Zaeed DLC, start Zaeed's personal quest and find a flamethrower (heavy weapon) near the end of the quest. |
M-622 Avalanche | Unlock this weapon by developing M-622 Avalanche technology. |
Mercenaries: Blue Suns | Talk to Tarak and Jentha (Omega - Archangel's base). |
Mercenaries: Eclipse | Talk to Jaroth (Omega - Archangel's base). |
Mercenaries: The Blood Pack | Talk to Garm (Omega - Archangel's base). |
Migrant fleet | Talk to Tali about her personal quest. |
ML-77 rocket launcher | Unlock this weapon by developing ML-77 rocket launcher technology. |
Normandy armor upgrade | Develop Heavy ship armor technology. |
Normandy shield upgrade | Develop Cyclone shields technology. |
Normandy SR-2 | Finish the prologue. |
Normandy weapon upgrade | Develop Thanix cannon technology. |
Omega | Take your first trip to the Omega station. |
Perseus veil | Start Legion's personal quest. |
Pragia | Take your first trip to the planet Pragia. |
Purgatory | Talk to Warden Kurik while trying to recruit Subject Zero (Prison ship Purgatory mission). |
Rakhana | Talk to Thane on board of the Normandy. |
Reapers: Indoctrination | Listen to a message on a terminal found on the derelict Reaper ship (one of the main quests of the game). |
Revelations | Purchase this magazine from the Zakera Cafe store (Citadel). |
Rise of the Alliance | Read an e-mail from admiral Anderson as soon as you've boarded the new Normandy. |
Security mechs | Defeat LOKI and FENRIS mechs for the first time during the prologue mission on Freedom's Progress. |
Ships: Dreadnoughts | Purchase a model of the Destiny Ascension ship from the Citadel Souvenirs store (Citadel). |
Ships: Frigates
| Purchase a model of the Normandy SR1 ship from the Citadel Souvenirs store (Citadel). |
Sovereign | Purchase a model of the Sovereign ship from the Citadel Souvenirs store (Citadel). |
Space combat: Pursuit tactics | Examine flight controls on Normandy's second deck. |
Starships: Quarian liveships | Get on board of a ship of the migrant fleet (Tali's personal quest). |
Tuchanka | Take your first trip to the planet Tuchanka. |
UT-47 Kodiak drop-shuttle | Examine a monitoring station on Normandy's fourth deck. |
Vorcha | Talk to a sick batarian (Omega - Slums). |
Weapon: Disruptor torpedoes | Examine a monitoring station on Normandy's third deck. The station is located in the main battery room and it can be accessed after you've recruited the Archangel. |
Weapon: Javelin | Examine a monitoring station on Normandy's third deck. The station is located in the main battery room and it can be accessed after you've recruited the Archangel. |
Weapon: Mass accelerators | Buy an item from Marsh's store (Omega market). |
Zorya | Install Zaeed DLC and recruit Zaeed for the team (Omega). |