WARNING: The following article contains spoilers from "Death in Four Dimensions" in Fantastic Four #35, on sale now from Marvel Comics.
Although Reed Richards is one of the smartest people in the Marvel Universe, he is also one of the most curious and always wants to learn more. His obsessive thirst for knowledge and discovery is largely what fuels the adventures of the Fantastic Four. But sometimes, that curiosity leads to discoveries that are more about himself than the world around him.
A scavenger hunt across time brought to light a new facet of Reed's family history in "Death in Four Dimensions" from Fantastic Four #35, by Dan Slott, John Romita Jr., JP Mayer, Scott Hanna, Cam Smith, Rafael Fonteriz, Mark Morales, Erick Arciniega, and VC's Joe Caramagna. He always knew his father, Nathaniel Richards, had relationships with others after leaving Earth, but what he didn't know was that he had a second family on Earth, leaving Reed with a sister that he never knew existed.
Although Nathaniel has openly admitted that he wasn't a good father, he and his son connected through a shared love of science. After Reed's mother passed away when he was seven, Nathaniel comforted his son by encouraging his pursuit of knowledge, instilling the love of exploration and discovery that has been a part of Reed's life ever since. It can be argued that, by teaching his son to reach for the stars, Nathaniel inadvertently made it possible for the Fantastic Four to exist.
First appearing in John Byrne's Fantastic Four #272, Nathaniel Richards was a scientific explorer and adventurer long before Reed. He joined a secret society and due to his exploits with them gained the ability to travel through time. However, this came at the cost of gaining the attention of Immortus. Forced to flee the time-traveling villain, Nathaniel left his family behind, but not before he made sure that Reed was financially secure for life.
He ended up traveling through alternate universes, building new relationships and even new families during his odyssey across time and space. This was no secret to Reed by the time the two had their emotional reunion. But deep down, Nathaniel harbored feelings of guilt for not being there for his son.
Regardless, Nathaniel was proud of the man his son had become and believed in his mission. Reed would still make discoveries and inventions that would improve the world. He was smart enough to do that, but also wise enough to know that family is the most important thing of all. He saw that Reed could have the best of both worlds because he found a balance and respect for both. But Nathaniel still had a secret that he never revealed to Reed during the course of his life.
A holographic recording revealed that Nathaniel had a second family on Earth. No further information was given beyond the fact that Reed had a sister that he never knew about. In the recording, Nathaniel asked Reed to find his sister, no doubt trusting in his son's abilities until the day he died. Nathaniel was also asking that Reed give his sister something the elder Richards never could: a family.