Keep staggering forwards until you reach the central room inside the Citadel; when you get here you’ll begin your final conversation with The Illusive Man. If you’ve been using the persuasion options in your previous conversations you have options available to you now that you wouldn’t have had otherwise.
We’ll not spoil the options of this interesting conversation, but suffice to say that sometimes sudden Renegade options are really just Paragon options in disguise…
The Final Choice (Obvious Spoilers)
Once you reach the upper lair of the Citadel you’ll be presented with a number of different options depending on how many War Assets you finished with. But essentially it boils down to three things:
Blue = Control the Reapers;
Red = Destroy the Reapers;
Green = Join Synthetics and Organic lifeforms to create a hybrid race (this is only available if your Military Strength was high enough).
Make your choice and enjoy the ending. Do note that trying to kill the Star Child results in a game over screen. This is not an option (trust us, we tried!)