Question: Dan Stevens stars as a fictional superhero who is the muton son of Professor Charles Xavier and who?

Context paragraphs:
Lilandra Neramani: Lilandra Neramani is a fictional character appearing in American comic books published by Marvel Comics, most commonly in association with the X-Men.  She is the Empress, or Majestrix, of the Shi'ar Empire and shares a lifelong bond with the leader of the X-Men, Charles Xavier.  She and Xavier were married, but their marriage was annulled after the Cassandra Nova incident.

Dan Stevens: Daniel Jonathan "Dan" Stevens (born 10 October 1982) is an English actor.  He is best known for his role as Matthew Crawley in the ITV acclaimed period drama series "Downton Abbey".  He also starred as David in the thriller film "The Guest", Sir Lancelot in "", and as The Beast/Prince in Walt Disney's live action adaptation of "Beauty and the Beast".  Since 2017 he stars as David Haller in the FX series "Legion".

Professor X: Professor Charles Francis Xavier (also known as Professor X) is a fictional character appearing in American comic books published by Marvel Comics and is the founder and leader of the X-Men.  Created by writer Stan Lee and artist Jack Kirby, the character first appeared in "The X-Men" #1 (September 1963).

X-Men: Deadly Genesis: X-Men: Deadly Genesis is a comic book limited series published by Marvel Comics in late 2005 and early 2006.  The series was written by Ed Brubaker with interior art by Trevor Hairsine and covers by Marc Silvestri.  Starring the X-Men, this series celebrates the 30th anniversary of "Giant-Size X-Men" #1.  The plot deals with the X-Men looking for Professor Charles Xavier, who went missing after "House of M", as well as the appearance of a new, incredibly powerful mutant threat.

The Man Who Invented Christmas (film): The Man Who Invented Christmas is an upcoming British-American drama film directed by Bharat Nalluri, written by Susan Coyne, and adapted from Les Standiford's book.  It stars Dan Stevens, Christopher Plummer, and Jonathan Pryce.  Stevens will play Charles Dickens at the time when he wrote "A Christmas Carol", with Plummer playing Ebenezer Scrooge, while Pryce will play Dickens' father.  Bleecker Street will distribute the film in North America in 2017.  As of December 22, 2016, the film has begun principal photography.  It is scheduled to be released on November 3, 2017.

Cerebro: Cerebro (Spanish and Portuguese for "brain") is a fictional device appearing in American comic books published by Marvel Comics.  The device is used by the X-Men (in particular, their leader, Professor Charles Xavier) to detect humans, specifically mutants.  It was created by Professor X and Magneto, and was later enhanced by Dr. Hank McCoy.  The current version of Cerebro is called Cerebra, to be distinguished from the character of the same name.  Cerebro first appeared in "X-Men" #7 (1964).

Sage (comics): Sage, also known as Tessa, is a fictional character in the Marvel Comics universe.  She has most often been associated with the X-Men and the Hellfire Club, whom she spied upon for Professor Charles Xavier.

Patrick Stewart, roles and awards: The following is a list of theatre, film, and television credits for English actor Patrick Stewart.  He is known for his roles as Captain Jean-Luc Picard in the "Star Trek: The Next Generation" franchise and as Professor Charles Xavier in the "X-Men" film series.  He has also been the voice of Avery Bullock on "American Dad! " since 2005.  He won a Grammy Award in 1996 and is also a Tony, Emmy, and Golden Globe nominee.

Legion (Marvel Comics): Legion (David Charles Haller) is a fictional superhero appearing in American comic books published by Marvel Comics.  He is the mutant son of Professor Charles Xavier and Gabrielle Haller.  Legion takes the role of an antihero who has a severe mental illness including a form of dissociative identity disorder, in which each of his alternate personas controls one of his many superpowers.

X-Men: First Class: X-Men: First Class (stylized onscreen as X: First Class) is a 2011 American superhero film, based on the X-Men characters appearing in Marvel Comics.  It is the fifth installment in the "X-Men" film series.  It is both a prequel and a soft reboot of the franchise, the film was directed by Matthew Vaughn and produced by Bryan Singer.  The story is set primarily in 1962 during the Cuban Missile Crisis, and focuses on the relationship between Professor Charles Xavier (James McAvoy) and Erik Lehnsherr / Magneto (Michael Fassbender), and the origin of their groups—the X-Men and the Brotherhood of Mutants, respectively, as they deal with the Hellfire Club led by Sebastian Shaw (Kevin Bacon), who is bent on world domination.  The film co-stars Rose Byrne, January Jones and Oliver Platt.  The film also introduces new actors to the series including Nicholas Hoult and Jennifer Lawrence who, like McAvoy and Fassbender, reimagine popular characters from the franchise (Beast and Mystique) that have already been established in previous films, namely the original trilogy.

Supporting paragraphs: Dan Stevens Legion (Marvel Comics)
Answer: Gabrielle Haller