Geass:

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Lelouch vi Britannia (Lelouch Lamperouge): Lelouch’s Geass was given to him by C.C. and his power was “The Power of Absolute Obedience” meaning that the person(s) who he cast the Geass on would have to follow his orders precisely no matter what. Few people could hold it off for a while such as Euphemia and Nunnally because both of them didn’t want to obey their orders very badly so they fought it off for a few seconds using their willpower.

Charles zi Britannia: Charles has the Geass ability to erase people’s memories and even create new ones for them. As well as sealing people’s memories, he can also seal people’s physical abilities as shown when he used the Geass on Nunnally, causing her to believe that she was blind. Charles gave his power so he could become immortal.

Marianne vi Britannia: Marianne’s Geass lets her switch her spirit, including her powers, like Geass, into the body of another person, usually Anya. She can return to her body as long as it is in one piece and when she does this, she can speak with C.C. through minds. 

V.V.: Like his twin brother, Charles, V.V. has the power of immortality because of an Geass contract, making him very much like C.C.. Not only that, but V.V. can also give the Geass contracts to people like his brother and Rolo Lamperouge.

C.C.: C.C. is immortal like V.V. so she stays young her whole life. She can make Geass users through a contract with them and heals from any wound she gets, like being shot repeatedly with a gun.

Mao: Mao was given the Geass by C.C. and became a Geass user at age 6. His Geass ability was to read people’s minds but they have to be within 500 meters away. His Geass, like all Geass do if given enough time, becomes permanent, forcing him to hear the minds of people every time and everyday making him appear crazy.

Rolo Lamperouge: Rolo’s Geass made him a skilled assassin because he could freeze a person’s sense of time, enabling him to walk around freely during this time interval. The disadvantage about this is that when he is using his Geass, his heart stops, making it hard to maintain a long time freeze. 

Bismarck Waldstein: Bismarck’s Geass lets him see glimpses of the future. There seems to be no side effect to this, and he says that he only used it on Marianne. 

Geass Canceller: 

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Jeremiah Gottwald: The Geass Canceller was given to Jeremiah allowing him to stop a Geass while it is being active on himself or people around him. Unlike Lelouch’s, Jeremiah can use his repeatedly.