Accidentally traveling to the world of the comic version of Prince of Tennis caused a change in the world line.

The champion Rikkai University completed an unprecedented three consecutive national championships.

Kunimitsu Tezuka did not let injury ruin his three-year tennis career.

Echizen Ryoma has completely turned evil, and he firmly believes in staying in the American team and waiting for an opportunity to avenge Byodoin Phoenix.

...

The person who triggered this butterfly effect was a Quincy who escaped the large-scale [Sacred] punishment when Yhwach awakened and fled here.