Sure, you can defeat the Oni that are coming through the Gatest of Jigoku and stop their nefarious plans here in the regular world. But that will only work for so long. If one wishes to defeat them entirely, you must travel to the Oni's home plane and defeat them there. That's the story behind the Beyond the Gates of the Jigoku expansion for Okko Chronicles that's up on Kickstarter now.
From the campaign:
OKKO CHRONICLES is a game for 2-5 players which plays between 60-120 minutes. Set in the heart of the Palace of Mists, the legendary comic book hero Okko and his traveling companions must hunt down powerful Oni (demons) and thwart their dark conspiracies.
Beyond the Gates of Jigoku
This new expansion compels Okko and his band of intrepid demon hunters to pass through the hellish Gates of Jigoku to fight its demonic denizens in their own realm. But beware, for in the dark and desolate domain of the oni, their corruption is much more powerful than anything your adventurers have experienced in the world of the living!
This expansion gives you the opportunity to play new scenarios or replay your favorite scenarios, without the need for an Oni Player by introducing both cooperative and solitaire modes to your Okko Chronicles games.
The campaign's closing in on 6x funded with 15 days left to go.