Worlds

Worlds are a mechanic involving the use of several storylines introduced in Yo-kai Watch 3 and gets much more expanded in Yo-kai Watch 4.

Nate's World
This is the main playable world in the first 3 games and also appears in the 4th.

Nate Adams
Playable in: Every main game

Cameos in: Yo-kai Watch Blasters, Yo-kai Watch: Wibble Wobble, Yo-kai Sangokushi

Katie Forester
Playable in: Yo-kai Watch, Yo-kai Watch 2, Yo-kai Watch 4

Cameos in: Yo-kai Watch Blasters, Yo-kai Watch 3, Yo-kai Watch: Wibble Wobble, Yo-kai Sangokushi

Hailey Anne Thomas
Playable in: Yo-kai Watch 3

Cameos in: Yo-kai Watch 4, Yo-kai Watch: Wibble Wobble, Yo-kai Sangokushi

Unseen in: Every game preceding Yo-kai Sangokushi

Yo-kai World
This is a world available in every game so far but was expanded in Yo-kai Watch 3 and got even more expanded in Yo-kai Watch 4. It is used mainly for sidequests and game mechanics.

Natsume's World
This is the world that contains Shadowside Yo-kai and was introduced in Yo-kai Watch 4.

Natsume Amano
Playable in: Yo-kai Watch 4

Touma Tsukinami
Playable in: Yo-kai Watch 4

Akinori Ahiroshi
Playable in: Yo-kai Watch 4

Keisuke Amano
Cameos in: Yo-kai Watch 4

Shin's World
This is the world of Classic Yo-kai. It got a lot more expanded in Yo-kai Watch 4 and takes place in old Tokyo in said game.

Nathaniel Adams
Cameos in: Yo-kai Watch 2

Shin Shimomachi
Playable in: Yo-kai Watch 4

Itsuki Takashiro
Cameos in: Yo-kai Watch 4

Tae Arihoshi
Cameos in: Yo-kai Watch 4

Main Locations
Old Springdale (Yo-kai Watch 2)

Tokyo (1960's)

Kuroi World
This world is the only known Anime-only world so far but was teased in a splash screen at the end of a demo showcase but is still unconfirmed.

Kuroi Jibanyan
Cameos in: Yo-kai Watch: WIbble Wobble

Kuroi Komasan
Cameos in: Yo-kai Watch: WIbble Wobble

Kuroi Yo-kai Watch
Cameos in: Yo-kai Watch: Wibble Wobble

Main Locations
Springdale (Kuroi version)