Keep in mind that in the new Trivia Crack Ranking it is possible to descend from the League in every category, except Trainee I.
This is why once you reach the Genius League, we suggest you keep up your level to stay in that category and continue to enjoy the weekly rewards it offers.
Remember that in every ranking you'll see which position you need to occupy, so that you don't descend from the league. You can see this represented by green boxes. Once they turn red, you'll be in a descending position.
To access the ranking and check your position, go to the third icon on the lower bar on the game's main screen.