How does mass effect 3 end?

Answer 1

At the end of Mass Effect, Sovereign has attacked the citadel with its Geth allies. Shepard arrives at the citadel, and after reaching the council building, has to fight Saren for the last time. If Shepard is persuasive enough, he can break through Sovereign's indoctrination, and Saren will commit suicide. However Sovereign channels its will into the implants in Saren's corpse, reviving it for the final fight of the game. Once defeated, the feedback stuns Sovereign enough to drop its shields, enabling the fleet, and the Normandy, to destroy it.

As wreckage slams into the ground, it looks for a moment like Shepard didn't make it, however all is well. Depending on your previous actions, there are 3 events that play out with two outcomes each, making a total of 8 distinct endings.

Answer 2

It ends differently depending on your alignment (Paragon or Renegade) but basically you kill Saren, but while you are fighting you can open the doors of the citadel and let the alliance troops attack sovereign (killing the council) or you can save the council. Depending on your choice the old council will be saved or killed if you kill the council the neutral option is to let a new council of Turian asari and salarian retake control or you can create a new council solely of Humans. Saving the council will let you pick a human (either Anderson or udina) to join with them as a fourh seat.

Answer 3

Shepard chooses from four choices (If you have the extended DLC if not, it's just the first three decisions), Control synthetics, combine organics with synthetics, destroy synthetics or do nothing and the reapers win.

Answer 4

Depends on how you played the first two Mass Effect games, your decisions reflect on how this game is based.