If you know anything about Legion from the X-Men comics, then you are most certainly curious about how the FX show is handling David Haller's father so far. Yet, there is plenty of mystery surrounding what happened to David's mom on Legion as well. During the Feb. 22 episode, the character from the frightening children's book, The World's Angriest Boy in the World, came to life in David's memories. As the character cuts off his mother's head in the book, it doesn't seem that far off base to wonder if David killed his mom on Legion. While I have a hard time believing that David was intentionally a murderous child, he has been keeping secrets about his past during his memory work with Melanie and Ptonomy. It's not clear what's real and what's fiction, but perhaps David was somehow responsible for his mother's demise and that's why his memories are not only so scattered, but also so unsettling.
Before a manifestation of the world's angriest boy was revealed in David's memories, the Devil with the Yellow Eyes had been creepy enough on his own. These two figures were not seen by Melanie and Ptonomy, but Syd was able to see the papier–mâché head of the angry boy. Then, the Devil with the Yellow Eyes crushed Melanie's hand in The World's Angriest Boy in the World book, so it sure seems that the contents of this book hold a secret about David's past with his mother.
David is an unreliable narrator when it comes to his memory work sessions and he could be hiding what actually happened to him as a child. Although his sister is still alive (for now), the man that David thinks is his dad (assuming his parentage on Legion will match what happens in the comics) died last year. The whereabouts of his mom are unknown, though in the first episode, he heard his mother saying how she loved him and in the second episode, he seemed particularly touched to see his mom in his memories. As he's unable to control his powers in the present, maybe David did accidentally cause her pain when he was a child even though his memories of his mother have been very sweet up until now.
Something else that's interesting to note is that his therapist Dr. Poole seemed to coerce David into saying in Episode 2 that he was that angry boy in the book from his childhood. So, perhaps David didn't hurt his mom, but he blames himself for or is emotionally scarred by something that happened to her. For instance, David revealed a stressful time in his childhood when he was trick or treating with his sister on Halloween. His dog King ran away into an abandoned house and David saw the angry boy there while his father's voice could be heard reading from the book. Does that mean his father (or stepfather) hurt his mom? Or that David had discovered his mom's dead body as a child?
In the comics, David's origin story is drastically different with his mother, Gabrielle Haller, being a survivor of the Holocaust. She became pregnant with David in Israel by Professor X and later, she lives in Paris as the Israeli ambassador to Great Britain with her son. David doesn't know the identity of his real father for some time, but he does have a stepfather in Daniel Shomron. That makes David's projections of his life growing up in the country on Legion completely different than what his comic counterpart experienced growing up.
Because of these massive differences, fans can't use the comics as a way to figure out what happened to his mom on the show, though I guess it's good to know that David did not physically harm or kill his mom in the comics. So until David stops creating memory barriers for Melanie and Ptonomy on Legion, what happened to his mother will remain a mystery — but I have a sinking feeling that the world's angriest boy will be returning in some form or another.