Half-phantom
Creature Type: Humanoid
Size: Medium (about 4–7 feet tall) or Small (about 2–4 feet tall), chosen when you select this species.
Speed: 30 feet
Two worlds. You have a separate ghost body, that usually takes form of a formless white phantom that has Incorporeal Movement (You can fly and move through other creatures and objects as if they were Difficult Terrain. You take 5 (1d10) Force damage you end your turn inside an object.)
It feels warmer than normal phantom on touch or passing through. You can also feel, hear and see through this phantom body, but cannot talk. You share HP with this body, but this body has same Resistances and Immunises as a Phantom.
Battle form. By spending an Action you can change the form of your second body. It copies your physical form, copying your equipment, and allowing you to attack or cast spells from their position, but cannot fly, move through objects, and loses Resitances and Immunities that it got from the previous ability.
Ghostly life. While not being youkai and looking like humans, they are a lot more long-lived than humans. Their humanoid physical bodies also feel a bit cold on touch.