During the mission Reaper IFF in Mass Effect 2, you'll come across a geth who is surprisingly not hostile towards Shepard and their squadmates. Additionally, the geth even helps to save Shepard from some husks and greets Shepard by name afterward.
Shepard will decide to take the geth aboard the Normandy after it is deactivated by a husk attack, however, this leads to the choice of whether to keep the geth or sell it to Cerberus. The choice you make not only affects Mass Effect 2 but also has consequences in Mass Effect 3. Here's a guide on what happens depending on the choice you make.
Decision Point for the Geth
On your return from Reaper IFF, a cutscene will play where Shepard, Miranda, and Jacob discuss what to do with the geth you retrieved.
Miranda wants you to sell it to Cerberus who have been looking for an intact geth for years. Miranda states that it can then be used as a weapon against the reapers. Jacob, on the other hand, wants you to throw it out of the airlock as it is a danger.
You can choose "Cerberus gets this geth" to sell it, or "I want to talk to it first" to keep it. Should you decide to keep it, the geth will remain deactivated in EDI's AI Core until you go and re-activate it, at which point you can talk to it.
Consequences
If you keep the geth:
- You gain 20 Paragon points.
- If you re-activate the geth, you will gain Legion as a squadmate.
- In Mass Effect 3, if both Tali and Legion survive the Suicide Mission, you can broker peace between the quarians and the geth in Priority: Rannoch, providing you have high enough Renegade or Paragon points. As a result, you'll earn two War Assets instead of one.
If you sell the geth to Cerberus:
- You gain 20 Renegade points and 50,000 credits.
- In Mass Effect 3, it is impossible to resolve the conflict between the quarians and the geth peacefully without both Tali and Legion during Priority: Rannoch. This means you'll be forced to pick a side, the race you don't support will become extinct. You will only receive one War Asset as a result.
- In Mass Effect 3, Legion will be encountered as an enemy you must defeat during Priority: Cerberus Headquarters.