In 1945, an accident caused Grindelwald to travel from Duel Heights to the wizarding world in 1991. However, he did not understand 1991, and with the changes in the timeline, the whole thing became confusing. As everyone knows, this has a huge connection with Voldemort, who was supposed to be on the rise but failed to achieve anything...
Intention: "The phoenix screams and flies to the vast sky, and the fire dragon roars back to the endless land. I don't care about fate, I only want to cross the fleeting years and come to you."