After defeating McKraken once and for all, Whisper seals the Yo-kai Elevator. But Lucas makes it possible for the Yo-kai to return! Find out about what you can do in the post-game.
Intro to the Post-Game
It turns out that Lucas made it possible for the Yo-kai to return, but a really long time passed before they could come back, and yet it is still summer break for you. Whisper says that one of the seals may have weakened when the Yo-kai came back. It's in the Infinite Inferno, and the entrance is supposedly in the Yo-kai world, but nobody has ever found it. There is also an extremely dangerous Yo-kai there that could destroy the human world. Supposedly, a very wealthy human has information about it. So one of your tasks in the post-game is to find that wealthy human to learn more about what to do.
Rank S Challenge
Now that you have completed the main story, you can visit Mr. Goodsight at Timers & More to begin the Rank S Challenge, which will allow you to upgrade your watch to Rank S! You have to defeat Yo-kai in the Yo-kai World. To find them, you have to fall off of the ledges to reach areas below the clouds: Impass is on Liar Mountain, Appak is on Hooligan Road, and Timidevil is in Hungry Pass. You can't defeat random Yo-kai to complete this quest: look for the ones that are marked by blue flags in the map.
The Timidevil can be found in the southern part of Hungry Pass. The Impass can be found in the southwest part of Liar Mountain. The Appak is in the western part of Hooligan Road.
The Stone Family
Your destination is Breezy Hills. The northernmost house is where the Stone family lives. Talk to the old man and he will mention dreaming of a tunnel west of Blossom Heights. When you try to leave the house, Mrs. Stone says that the place that Mr. Stone mentioned was not a dream. They have been there many times. But Mrs. Stone says that one day she sensed something very sinister from the locked hut in that meadow, so they never went back, and Mr. Stone lost his memories of the place. But Mrs. Stone found a key on that last visit, so she gives it to you.
Go to the Temple in Blossom Heights. There is a place west of the Temple where you can walk through the guard rail of the road. This leads to a long tunnel that goes to a grassy meadow. There is a hut in this meadow. Check on the door a couple of times to unlock the lock. Then you can climb down the ladder to reach the Infinite Inferno. It is full of challenging Yo-kai, as well as much stronger versions of previous bosses.