Callum Turner plays Theseus Scamander, older brother of Eddie Redmayne's main character, Newt Scamander. Theseus is an Auror, and both brothers seemed to carry a torch for Zoë Kravitz's Leta Lestrange. Theseus was engaged to Leta in Fantastic Beasts: The Crimes of Grindelwald, but she sacrificed herself and at least appeared to die. It's not clear if we'll see Leta again in any form. But Theseus will return. We last saw him at Hogwarts with Newt and Team Dumbledore, with Credence and Queenie at Nurmengard on Team Grindelwald.
Now what? Well, Callum Turner recently talked to Yahoo Movies UK to promote his new movie Emma. During the discussion, he was asked if he would return for Fantastic Beasts 3, and he said he would return in about six weeks. The interview was conducted on January 15, so six weeks from that point would fit with a late February 2020 filming start date. February is the most recent filming date we heard from Dan Fogler (Jacob Kowalski), so that fits.
As to what we can expect? "No idea," Callum Turner said -- and Yahoo noted that, off-camera, he said he hadn't even seen a script yet.
That also kinda fits with the most recent Fantastic Beasts 3 updates. The movie was initially going to start filming in summer 2019 but that was delayed to fall, due to the "gigantic" size of the production. That's what Dan Fogler said, adding that the cast was told the third movie was going to be twice the size of the second one. (Interestingly enough, Dan Fogler is about half his size from the second movie after losing a ton of weight.)
We knew Fantastic Beasts 3 planned to be set in the 1930s, including time in Rio de Janeiro, Brazil -- but also more time at Hogwarts, and also a visit to Ilvermorny School of Witchcraft and Wizardry, the North American school of magic. There's a lot going on.
However, filming did not start in fall 2019, it was delayed to spring 2020. Not only that, J.K. Rowling was revealed to still be working on the script -- and this time, Warner Bros. got her back-up from Harry Potter screenwriter Steve Kloves. She wrote the previous two Fantastic Beasts scripts on her own, but disappointment over the performance of the second film seems to be a real reason for Fantastic Beasts 3's delay, to make sure they make the best movie possible.
Jude Law recently talked about J.K. Rowling spending almost three straight hours pouring out all of Dumbledore's backstory, which should be very key to the future Fantastic Beasts movies. The five-movie plan reportedly ends in 1945 with that major Dumbledore/Grindelwald duel. In the meantime, we should get "answers" -- per J.K. Rowling -- on the many mysteries, including what's really going on with Credence and the connection Grindelwald said he had to the Dumbledore family.
Fantastic Beasts 3 is currently scheduled for release on November 12, 2021. Hopefully we start hearing more about the movie soon, since it's meant to start filming in just a few weeks.