User blog comment:Crimson and Darkness/DxD Updates 2~/@comment-2600:1700:14E1:4110:CCF0:76A5:7D88:C6F2-20190622145720

Maybe in shin dxd vol 3 we'll learn more about youkai, as well as the 13 different types of kitsune.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.mythicalcreaturesguide.com/m/page/Kitsune&ved=2ahUKEwiKpO2ErP3iAhURO60KHZ88AeEQFjAMegQIBhAB&usg=AOvVaw1ob6WMHIQt4DQ4usiWT1hZ

https://teenwolf.fandom.com/wiki/Kitsune#Real_World_Myth