Some of the creatures are among the deadliest in the wizarding world, so when they get loose, trying to get them back is crucial. Meanwhile, the rise of the Second Salemers—possibly aided by someone from the inside—will surely throw a wrench in things. A standoff seems imminent.
Harry Potter will notice that MACUSA (the American wizarding government) president Seraphina Picquery makes a connection to Gellert Grindelwald nearly 20 years before Albus Dumbledore would take him down. If she’s referencing him, that’s not a good sign.