Every single anime and cartoon is in the same world, just in different time lines or different countries. For example: Oraun high school is in the future in Japan [For in the live action version Kyoya has a hologram] while Family Guy is in the same detention just in America and in the present. And when a character dies their soul is transferred into another body with no memory of their past lives. There are other universes only with video game characters being dominate and other universes with robots or anything else you can think of.
Summary: Haruhi is keeping a secret. A big one that will change how people will look at the world. When the Hosts find a mysterious journal and USB, they discover her secret and it changes everything.
This idea is a Crossover with the Ouran Host Club Fandom and the PowerPuff Girl Z Fandom if you do not like the idea than i will not bother with it. Thank you and have a wonderful day.