Origin

The M Twins' power is great. They possess a high degree of telepathy, able to use it in limited offensive capabilities such as and can open inter-dimensional gateways into alternate planes of existence. As revealed in a flashback in Generation X #40, the twins opened a doorway to another dimension to imprison their villainous brother Emplate as a punishment for his suspected (later discovered to be actual) involvement in their mother's death and their sister M's disappearance.

Nicole and Claudette also possess a rare power called "gestalt." With it, they can (and have) physically merged with with Marius (Emplate), Monet (M), Hollow or any combination thereof. Each combination has a new, different personality and set of powers. A simple example of a gestalt: When they were masquerading as their older sister Monet, they possessed many abilities, not all of which may have actually existed in the real Monet.

Phalanx

During the Phalanx Arc, The M-twins are in a limousine. With a colonel who is complaining about Monet not talking. She tells her if she say anything her dad might send her to get help from Xavier in the states who deal with mutants. The car then turns off and nothing in the car works. It crashes against a rail. In front of the car is a phalanx who absorbs the driver. It goes to the back of the car to get Monet, the colonel throws Monet out of the car and tells her to run for her life. She then shoots the phalanx to no result only to be absorbed by it. Monet just stays in the same place. The phalanx tries to make a biocentric scan of Monet but he says there is too much intense psionic energy blocking him from doing it. The phalanx then states that the being might be the most powerful of the next generation of homo superior. Monet is then seen in a chamber with skin, Paige, cannonball and blink. They still make no contact with the other people. She then tells them to be quiet. Monet is was making a device that would get them out this device showed that Cannonball was part of the phalanx. The phalanx then turns to stone. Monet already knew cannonball was a phalanx. And tells the others there are few things she doesn’t know. She then tells them that the phalanx placed him in here as a spy. She then tells them the device she made also put a illusion to the other phalanx that they are still in the room while they escape.

Generation X

During Generation X the Twins were masquerading as Monet and nobody knew. M-Twins first appeared as the kids were being gathered together to go to school. She makes a comment on how mutants shouldn't hide their abilities and should be proud of them. When she comes in she asks Cassidy to get her bags, he says yes to 3 trucks full of bags. They are the first ones who want to go to the training session. M-Twins like to climb trees even though they can fly. In the first issue we see them talking to Gateway. They then figure he came here to tell them Marius their brother is back. They go to the airport to get Chamber when he is attacked by Emplate. The M-Twins go to attack him but is held telepathically by Emma Frost. M-Twins didn't like it that much and yelled at Emma never to try that again.

The M-Twins demostrate how much Penance is like emplate to the others. She figures out that Penance was used as a source of food for Emplate. They go with the rest of the group to look for Penance after she escapes.

The real Monet, as some in Generation X have noted, is actually even more obnoxious than the twins when they were impersonating Monet. Thus, the Monet that the twins became had a personality and powers that differed from their own as well as that of the real Monet. When any siblings are merged using the gestalt ability, they become privy to each other's deepest secrets and fears; this is attested to by Marius after a gestalt in which the twins and Emplate became an entity called M-Plate. In fact, it's how the twins learned that Marius killed their mother, a chilling fact he later revealed to Monet and their father.

When the M Twins were masquerading as their older sister M, they called the mysterious mutant Gateway mentor. It's likely that Gateway knew that this Monet was actually the St. Croix twins.

When last mentioned, the twins were returning to live with their father in Monaco, Algeria. It's unknown how, if at all, they've been affected by Decimation.

Alternate Realities

In the AoA universe, the twins were known as "The Monets" and aided Emplate.