When you go through walls your will not come with you. You must spend at least a short rest with each item for it to stay with you when you use your ethereal form or possession. If you do not spend t in mes with these items they do not go with you and drop to the floor.

As being classified as undead you 2 times the damage to radiant damage. But you are resistant to Bludgeoning, Piercing, and Slashing from Nonmagical Weapons damage.

One thing that keeps you on the material plane is an object. Either the player or the Dungeon Master can pick the thing the character is Soul Bound to and you must be Soul Bound to something. You can either be Soul Bound to a living creature or an object in the world. When you are Soul Bound to something you can only stay in a 120 foot radius of the of object. You are stuck in the radius from the object and if you try to leave the 120ft an invisible forcefield keeps you from leaving. When the object is moved and you are at the 120th foot you are pulled along by the force field. You cannot move your Soul Bound object, only a living creature may move the object. If either the  creature dies or object is destroyed you drop to 0 hit points and have to make death saving throws. When your object is destroyed and you succeed the death saving throws you or your Djngeln Master picks something within 120 feet from you to be Soul Bound to.

Your creature type is humanoid and undead. You do not require air, food, drink or sleep. You are immune to poison, being poisoned and diseases. Due to your lack of a physical body, you are immune to the state of exhaustion.

You may move through objects and creatures as if they were difficult terrain. Ending your turn in a square occupied by an object or creature causes you to be pushed to the nearest unoccupied square and take 1d10 force damage. All of your items that you have spent time with (see Ghostly Objects) enter your form as you go through objects.

You gain the ability to possess a humanoid within 5 feet of you. The humanoid must succeed a Charisma saving throw or become possessed. You then disappear and all of your items go into your form as long as you have spent time with (check Ghostly Objects), and the target is incapacitated and loses control of its body. You now control the body but you can't deprive the possessed target of awareness. You can't be targeted by any attack, spell, or other effect, except ones that turn undead, and you retain your alignment, Intelligence, Wisdom and Charisma scores. You otherwise use the possessed target's statistics but you don't gain access to the target's knowledge, class features, or proficiencies. The possession lasts until the body drops to 0 hit points, you end it as a bonus action, or you are turned or forced out by an effect like the dispel evil and good spell. When the possession ends, you reappear in an unoccupied space within 5 feet of the body. The target is immune to your Possession for 24 hours after succeeding on the saving throw or after the possession ends. You regain use of this trait once you have completed a long rest.

As a ghost you are granted 30 feet of darkvision.

You can float no more then 5 feet off of the ground. When you fall you take no damage.

You were living once. As such you gain ability score increases, speed, alignment and size of your form before death. However, as a ghost, you lose the traits that your race may have had when you were alive- for example, an Elf Ghost has none of the Elf race traits; just ability score increases. You still have a physical presence- meaning physical weapons affect you as they would for any other race.

As you are putting all of your soul essence on this plane it could be quite hard to live there. If you fail all of your death saving throws and your character dies you cannot be brought back to life. When you die your ghostly form phases away. You cannot be brought back in your ghostly form or your physical form  for your soul is eliminated once you die. You do have the ability while you are an alive ghost you can have use or have someone use the resurrection spell on your physical body and be brought back to life. But if you die as a ghost a resurrection spell will not work on you.