Someone posted a thread about hidden instances in the game. This is a description on the Kappa and their love of human colons. In Nioh 2, when they grapple you, they appear
Nioh 2 All Types of Yokai (Enemy Locations)
Yokai Country (DotN DLC) - Nioh Walkthrough - Neoseeker
Kappa Shell | Nioh Wiki | Fandom
Kappa | Nioh 2 Wiki
I finally got my platinum! : r/Nioh
Nioh 2 Kappa soul core farming - YouTube
Indestructible Shell | Nioh 2 Wiki
Kappa | nioh Wiki
Preview: Nioh 2 heavily improves upon while adding brand-new features