Your Intelligence score increases by 2, and your Wisdom increases by 1. However, your Strength score decreases by 2, and your Dexterity decreases by 1.

Geists don't age, as a form of undead without a physical body they can last for as long as they continue to hold onto this realm of the living but most will dissipate after about a 1000 years.

Geists tend to retain the alignment they had in their life or be within one factor of their original alignment.

The height of a geist varies based on the geist's original race, however, regardless of your original race. Your size is Medium.

You have a base walking speed of 30 feet.

Your ethereal form grants you a host of benefits. Your Armor Class is calculated using your Intelligence instead of your Dexterity. While unarmored your Armor Class is equal to 10 + your Intelligence modifier. You are resistant to nonmagical bludgeoning, piercing and slashing damage. In addition, you may free swap your walking speed for a hover speed equal to your walking speed.

A geist can see 60 feet into the Ethereal Plane when it is on the Material Plane, and vice versa. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

A gheist does not use physical strength to lift objects due to their form, instead, they use their influence over the ethereal. You may use your Intelligence score in place of your Strength or Dexterity scores and may manipulate objects you can see within 5 feet of you. For example, you would make a Intelligence (Athletics) check to grapple a target instead of a Strength (Athletics).

Like most spectral undead, physical structures do not impede you. You can move through other creatures and objects as if they were difficult terrain. You take 1d10 force damage if you end your turn inside an object.

You know the thaumaturgy cantrip. Intelligence is your spellcasting ability for it.

You don’t need to sleep. Instead, you reconnect to the energies that sustain you, remaining semiconscious, for 4 hours a day. While doing this, you dream in a fashion; such dreams are actually the pull toward the Æther. After resting in this way, you gain the same benefit that a human does from 8 hours of sleep.

Your creature type is undead. As a form of undead, you are not healed by healing spells and other effects that would target humanoids. If you die, you are sent to the astral plane for 1 year and then return to where you died. In addition, you don't require air, food, drink, or sleep.

While your form grants you a host of benefits it has a number of flaws as well. You have disadvantage on Strength and Dexterity saving throws. Your hit point maximum decreases by 1, and it decreases by 1 every time you gain a level. You are forbidden from entering locked areas, consecrated ground areas such as temples and shrines, or passing over a circle of salt. In addition, you are vulnerability to radiant damage.

You are able to speak, read and write Common and one extra language of your choice. This is usually one of the languages you knew before death.

As a type of ghost, the process of returning to the realm of the living has taken its toll on you. As such you have been afflicted with one of the following indefinite madnesses. This madness cannot be cured.