I recently checked out Fantastic Beasts And Where To Find Them, mainly because my wife is a huge Potterhead (not gonna lie, I find the series super charming as well), but also because the dude from Balls of Fury was in it.
And although my knowledge of Potter-lore pales in comparison to my wife's, I still have a good grasp on the basics. Like a general timeline of events and that Voldemort, despite being a super evil being, is a relatively new one; he's predated by the events of Fantastic Beasts by a few decades, as the movie's set in 1926.
However, believe that Beasts' tortured villain, Credence, is definitely connected to he-who-shall-not-be-named in some not-so-tenuous ways.
The insane obscurus power that Credence possesses and how a piece of him seemingly escapes at the film's conclusion when he's been "destroyed" strongly suggests that the series isn't done with the boy-with-the-weird-haircut (his new name now, deal with it).
A theory fans have been tossing around is that Credence is actually Tom Riddle Sr., pappy to old no-nose, but there are some problems with that.
First, Credence is a Muggle as far as we know. He's not British, either, so him being Voldemort's daddy isn't really all that viable. But related, yeah, that is entirely possible. First of all, Voldemort is unclear on his family origin and let's not forget his maiden side, the Gaunt family, is linked to the Slytherins.
Some people think Credence and Voldemort could somehow be twins. When you see how pale and black-haired they are, it makes sense.
Credence's family tree is murky and Mary Lou Barebone hints that he comes from a wizarding background.
She insinuates that Credence is a witch (before he kills her), so it could be that Credence is some long-lost cousin or part of Voldemort's family tree, somehow.
His power is just too dark and immense.
In the film, when Credence loses control, he allows his obscurus to just tear house on everything. Buildings are destroyed, skies are clouded, I mean the guy is an absolute tornado of dark wizardry. He had to have gotten this wizarding power from somewhere. It's more likely inherited from a long-line of powerful wizards, like Voldemort's family, perhaps, maybe?
Credence's "death" could've been an inspiration for Voldemort and his horcruxes.
Look, it's basically been confirmed by the Beasts director that Credence survived his magical massacre at the end of the film. Credence's ability to preserve himself could be where Voldemort gets the idea of preserving his essence in horcruxes. One theory even suggests that Credence's soul could eventually end up in Voldemort's body when he's born, making Voldemort a horcrux himself. Whoa.
Obviously the only one who knows the answer to all of these questions is Queen Rowling herself.
And although I know more about the mythos (if you can call it that) of the Lethal Weapon universe, I'm definitely down to see what she has in store for these characters.