Fantastic Beasts 4, in six major ways. The Secrets of Dumbledore is the third movie out of what was originally planned as a five-movie franchise, meaning a fourth is a possibility, albeit an unlikely one given the film's disappointing box office score and critical reception. While the chances of a sequel at this point are likely low, The Secrets of Dumbledore still includes several things that could be capitalized and expanded on in Fantastic Beasts 4.
The franchise is a prequel to the Grindelwald, played by Johnny Depp before Mads Mikkelsen took on the role, was a childhood friend and lover of Albus Dumbledore, played by Jude Law. However, early in their relationship when the two were still in love, Dumbledore and Grindelwald made a blood pact when planning their magical revolution meaning neither could oppose the other.
When Grindelwald's dark ways began to show, Dumbledore, realizing he was blinded by his love for Grindelwald, cut ties with him. Following a duel between the two and Albus's brother Aberforth, that tragically led to the death of Ariana Dumbledore, Grindelwald fled the country in a search for power while Albus began teaching at Hogwarts. This leads directly into the events of Dumbledore enlisting the help of Newt Scamander to oppose Grindelwald as he can't directly due to the blood pact. However, Fantastic Beasts: The Secrets of Dumbledore includes many things that can lead to a sequel.
Dumbledore Can Now Openly Oppose Grindelwald
Arguably the most important way this is done comes towards the end of the film. In the final act of The Secrets of Dumbledore, Grindelwald is trying to falsely elect himself as the head of the wizarding world using a Qilin, a magical creature that bows to anyone pure of heart. In order to stop this, Dumbledore, Newt, and the rest of their team infiltrate the ceremony and expose Grindelwald. Grindelwald, in his rage, tries to kill Credence who is Aberforth's son and Albus's nephew. The latter two protect Credence, with the spells clashing causing Dumbledore and Grindelwald's blood pact to break.
This sets up what would surely be one of the biggest plot points of Fantastic Beasts 4 and even Fantastic Beasts 5. As mentioned above, the blood pact was of great importance to Dumbledore and Grindelwald's relationship. Through it, Grindelwald had eliminated the greatest threat to his quest for power by ensuring Dumbledore couldn't oppose him. However, now that the pact is broken, Dumbledore can directly challenge Grindelwald. This can lead to one of the most speculated aspects of the wizarding world's history, the legendary duel between Dumbledore and Grindelwald in 1945.
The Global Wizarding War Continues To Build Towards WW2
This duel ended both the Global Wizarding War and World War 2, with the wizarding and muggle wars coinciding between 1939 and 1945. When Fantastic Beasts and Where to Find Them was announced, it was confirmed the timeline of the series would culminate in the first Global Wizarding War in which Dumbledore defeated Grindelwald. With the first three movies in the series then, director David Yates and writer J.K Rowling have been slowly building up to this moment. The first and second movies take place in the mid-1920s, with The Secrets of Dumbledore being set in 1932, five years after Fantastic Beasts 4's story to be set around the late 1930s at the onset of WW2 and the Wizarding War. This would then lead to the final battle between Grindelwald and Dumbledore in 1945 in Fantastic Beasts 5.
Newt And Tina Can Rekindle Their Relationship
One of the most disappointing aspects of Fantastic Beasts: The Secrets of Dumbledore was the sidelining of Tina Goldstein, played by Katherine Waterston. Tina was the main love interest of Newt Scamander in the first and second movies. However, she didn't feature in the third movie in a significant way at all. With that being said, the ending of Fantastic Beasts 3 sets up a way for Fantastic Beasts 4 to rekindle Tina and Newt's relationship, despite the film only giving half-hearted reasons for her absence up to that point, and none that explain why it made any sense. Given how it is confirmed Newt Scamander gets married to Tina eventually in the Harry Potter universe, Fantastic Beasts 4 would be the ideal place to begin setting up that relationship.
At the end of the film, Newt attends Queenie Goldstein, Tina's sister, and Jacob Kowalski's wedding. Upon entering the bakery Kowalski owns in which the wedding takes place, Newt reunites with Tina who is in attendance. This, along with the death of Leta Lestrange (who was Newt's childhood love) in Fantastic Beasts 2, sets up the perfect opportunity for Fantastic Beasts 4 to offer a greater exploration of Newt and Tina's relationship that the third film was lacking. So far, the attraction between the two has been mutual, if a little bit awkward. Beginning with Fantastic Beasts 4, despite Dumbledore's poor box office, both the stakes of the Wizarding War and the intensity of Newt and Tina's feelings can be increased, going hand-in-hand with each other in of the plot, with the two potentially declaring their love for each other amid the war.
Tom Riddle Starts Hogwarts In 1938, Only 6 Years After FB 3
Another way that Fantastic Beasts: The Secrets of Dumbledore's timeline sets up Fantastic Beasts 4 involves the infamous Tom Riddle/Voldemort. As is known from the Harry Potter series, Voldemort was once Tom Riddle, a young boy from the Slytherin House at Hogwarts. Tom Riddle started Hogwarts in 1938, which is only six years after Fantastic Beasts 3 is slated to take place. Again, if the timeline continues to move towards WW2, there is no reason for Harry Potter's nemesis, Tom Riddle/Voldemort not to appear, even if only in a cameo role.
While Riddle wouldn't directly affect the plot of this specific franchise, it would be neat to see the connective tissue between the Fantastic Beasts series and its sequels being shown on screen. Most prequels of recent cinema, from the Star Wars prequels to The Hobbit trilogy, have had very overt and obvious links towards the end of their franchises that allow for an easier connection between them and their sequels. Fantastic Beasts 4 should be no different, and can even benefit the Harry Potter series retroactively by shining a greater light on Voldemort, Harry Potter's Grindelwald, by focusing on the boy that was Tom Riddle before his rise to power.
Queenie & Jacob Can Live Safely Away From The War
Jacob Kowalski has often been praised as a highlight of the Fantastic Beasts series thus far. That is largely in part to the fantastic portrayal by Dan Fogler, however, could also come from the heavier focus on a muggle, or no-maj, embroiled in a large-scale wizarding conflict. One thing that is a focus of Kowalski's character though, is his relationship with Queenie Goldstein. Queenie, on the other hand, has been a bit of a mystery in the series so far, with her easily-changing allegiances between Dumbledore and Grindelwald often being very thinly written. However, the ending of Fantastic Beasts 3 can provide a perfect ending for these characters.
Given the lack of depth given to Queenie's motivations in the two most recent Fantastic Beasts installments, the finality of her marriage to Jacob was refreshingly straightforward. One of the only things made clear about Queenie's character so far is her love for Jacob, and vice-versa. With their marriage then, which serves as the ending scene for Fantastic Beasts: The Secrets of Dumbledore, the two can live safely together away from the Wizarding War in Fantastic Beasts 4. It is likely that with Queenie's allegiance changing twice, and Jacob's muggle status, they would have had their fill of wizarding conflicts, and want to protect their newfound marriage by living safely out of the reach of Grindelwald. Also, as Grindelwald performed the Cruciatus curse, one of the Harry Potter universe's three unforgivable curses, on Jacob towards the end of Fantastic Beasts 3, he is likely done himself with the fight, opting to live in peace with his wife in Fantastic Beasts 4.
Aberforth and Credence's Relationship Can Be Explored In A Deeper Way
The way the plot was presented for Fantastic Beasts: The Secrets of Dumbledore, and how Credence's status as a Dumbledore was used as a major plot twist for The Crimes of Grindelwald, made it seem as if Credence and his relationship with Albus or Aberforth would be a vital part of Fantastic Beasts 3. Unfortunately, the film squandered this potential and didn't flesh out either Credence or Aberforth in any meaningful or sympathetic ways.
With Aberforth accepting his son, Fantastic Beasts 4 and Ezra Miller's involvement in it, remains to be seen. However, this is certainly one of the major ways, among many others, that Fantastic Beasts: The Secrets of Dumbledore set up more adventures in the wizarding world, beginning with Fantastic Beasts 4.