.hack//G.U. Returner

The characters from previous .hack//G.U. Games and .hack//Roots receive an email from Ovan.

He is requesting them to go to Hidden Forbidden Festival where is set up a mysterious summer festival.

There they find an AIDA Chim Chim who wishes to peacefully co-exist with the other players of The World.

It then transforms into the word "Returner", so they assume it to mean that Ovan will return to The World.