you were a new vocaloid, so you would be a new resident in each sekai, the fourth sekai would be the sekai of the group WONDERLANS X SHOWTIME, Wonderland sekai

you woke up on a amusement park, it was cool, suddenly, someone hugs you tightly, it's a boy, he has blue eyes and blonde hair with a little ponytail.

– welcome, new resident! I'm Len! come with me! i'll show you the others. – he says, grabbing your hand