Incorporeal creatures and etherealness

[Jackiboi]

One of my players can turn ethereal as per the spell due to a magic item I gave out. He will soon be going to a place where wraiths and the like are lurking.

Are there rules as written interactions between ethereal and incorporeal creatures? I picture ghosts as being halfway to the ethereal plane, and so in my mind this "cancels out" with ethereal characters, but now I look back to the rules they seem completely unrelated.

Should I house-rule something? Should I warn the player (who has no idea there are wraiths, but knows there are undead ahead) that there's still a risk of being seen by some creatures even though he's ethereal? I don't want to have a 'gotcha' moment, but also think it would be nice for ghosts to be able to see him.

I'm playing in Eberron, but I haven't looked into the cosmology too much and neither have the players, so the rules for the general structure of planes in D&D will do fine for me.

[Rafaelfras]

While on the Ethereal Plane, you can only affect and be affected by other Creatures on that plane. Creatures that aren't on the Ethereal Plane can't perceive you and can't interact with you, unless a Special ability or magic has given them the ability to do so.


Description
The ‘Inner Sea’ of the planes, the eternal fogs of the Ethereal Plane wash over all the Inner Planes. It is the echo of the Material Plane, a realm of memory and ghosts. Items and actions on the Material Plane create ripples in this fog and draw the attention of wraiths and worse from within the mists.




Etherealness: The ghost enters the Ethereal Plane from The Material Plane, or vice versa. It is visible on The Material Plane while it is in the Border Ethereal, and vice versa, yet it can't affect or be affected by anything on the other plane


Quoted the relevant text that might help you.

When incorporeal creatures are hiding in the ethereal they can be attacked by your ethereal character.
Wraiths, ghosts, spectres and the like can be found in the ethereal plane.
But as highlighted by the ghost ability not all of them can enter and leave the ethereal at will.

So there it is
In my opinion incorporeal creatures in the material are not subject from interactions on the ethereal plane.

[JackPhoenix]

So, the thing is... there aren't any incorporeal creatures. Not really. Wraiths have Incorporeal Movement ability that allows them to actively move through solid objects and creatures... and that's it. You can still beat one to death (again) with a random stick you've picked off the ground.

[Jackiboi]

Thanks a lot for the help! I'll play around with the possibility of putting foes on the ethereal plane that can't switch over to the material plane, as it looks like ghost-like creatures can be found on either plane but shouldn't be considered to be on both planes at the same time.

Also while there is no miss chance when targeting incorporeal creatures, they do tend to have lots of resistances so maybe that's how they decided to make attacks "pass through" incorporeal creatures. It doesn't have the same flavour as the attack missing entirely though.

[Psyren]

Only ghosts can become ethereal as written. If he is ethereal, he is completely safe from wraiths and spectres.

Even if you change that, moving them to the ethereal where they can interact with him, he can still defend himself, even without magic weapons.