The final episode will consist of Lelouch and Suzaku joining forces against Schneizel who has killed the Emperor.
Then Lelouch and C.C. will ride a mech with two pilot seats, and that mech will gattai with Suzaku's Lancelot, Kallen's Gurren, Toudou's Gekka, Jeremiah's Siegfried, and a few of the Knight of Rounds Knightmare(not Mordred, because Pinky is gonna die somewhere earlier, together with Rollo and his Vincent.}.
The Ultimate KnightMare will be named Arthur(with the cat Arthur at Suzaku's side.)
Schneizel is going to reveal his greatest project. A KnightMare with the power to USE the power of The Realm of Gods named Gilgamesh.
The final battle will take place in Charles's Sword of Akasha.
Gilgamesh will release a barrage of MVS and a giant blast from a giant Hadron Cannon.
While Arthur will release every weapon of all of the original mechs weapon arsenal.
Halfway through the battle, Lancelot will release itself from Arthur to show an opening.
As Lancelot is being obliterated by the hail of swords, the remains of Arthur run towards Gilgamesh and releases Jeremiah, who has vowed to protect Lelouch, crashing Siegfried onto Gilgamesh, destroying both KnightMares and killing both pilots of the mechs.
The ending scene shows C.C. disintegrating, Lelouch's Geass fading and Nunnally standing up, running towards her beloved brother.