Death doesn't have to mean the end for a character. With the Dungeon Master's blessing, a player can choose to have their character rise from the grave as a skeleton. All previous race/subrace traits are lost and replaced with undead traits.

An awakened undead character can return to the living through True Resurrection. A character that returns to life this way loses all of the ghost features and abilities and replaces those with the features and traits of the race and subrace they returned to from their Past Life.

Skeletons are commonly raised as mindless servants or soldiers by potent necromancers. They may also be the result of a curse that prevents a soul from truly passing on to the afterlife; perhaps thieving cursed valuables, or wronging a powerful being. Skeletons are often the remains of a mortal from decades or even centuries past, and their remains will reflect that. They might be nothing but dry bones cobbled back together with necrotic energy, or perhaps they still have vestiges of rotting or desiccated flesh dangling from their forms. The death of the master that raised them, a reconciliation or cleansing of the curse, can end up awakening a skeleton from its mindless service instead of returning it to death. 

Skeletons often experience the most confusion and disconnection with their previous life - they retain only fragments of memory that flow through their hollow skulls. The length of their death is reflected in their state of decomposition, which means that there is a great deal of time and distance from their mortal life. Skeletons are the least likely to try and re-engage in their old life, and are far more likely to strike out on adventure when they are freed from servitude.

Redead Traits

Your awakened undead character has the following traits. You count as an undead creature for all spells and abilities that affect the undead.

Ability Score Changes

Your Constitution score increases by 2. Choose either your Dexterity or Charisma score to increase by 2.

Undead Traits

Your awakened undead character has the following traits. You count as an undead creature for all spells and abilities that affect the undead.

Undead Nature

You are sustained by the necromantic energy that raised you from death. Your body is no longer affected by disease, poison or the poisoned condition. You don't require air, food, drink, or sleep. You have advantage on saving throws against exhaustion, but you do still need rest. Instead of sleeping, when you take a long rest, you enter an eerily still period of inactivity of at least 4 hours a day. During this period, you do not sleep or dream; you are not rendered unconscious, and you can see and hear as normal.

Undying Vigor

You are sustained by necrotic energy, which makes you resistant to necrotic damage. As undead, you can't be healed by conventional spells such as cure wounds, nor do you have the bodily means to ingest and gain the benefits from potions of healing, or consuming the products of spells such as Goodberry or Heroes' Feast.

You can gain or regain hit points through a short or long rest, or magically through the following spells: Aid, Aura of Vitality, False Life, Life Transference, Negative Energy Flood, Regenerate, Vampiric Touch, or Wish.

Your hit dice function as normally, except that you regain all of your hit dice after a long rest instead of just half your level.

Dead Lights

Dark magic glows in your sockets, whether there is flesh still there or not. You are able to perceive with clarity that which lurks in the darkness. 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. 

Past Life

You were once a living creature. Choose which living race you died as; this choice cannot be a construct. 

Past Life Traits

Some fragments of your original racial traits will remain. Your size, height, and race stay the same. You retain your skill and tool proficiencies, and any language you spoke in life. You can retain your personality and alignment, and memories of your past life, though they are often incomplete and hazy.

Skeletal Structure

Your lack of significant flesh is both a boon and a curse. Piercing weapons are less effective against you, but you have no fleshy padding to protect your dry bones from bludgeoning damage. You gain resistance to piercing damage, but are vulnerable to bludgeoning damage.

False Appearance

As a bonus action, you can reduce yourself to a pile of bones. While in this state, you are rendered prone, and you appear dead to all outward inspection and to spells used to determine your status. While in this state, you are blinded and incapacitated, and your speed drops to 0. You gain resistance to all damage except psychic damage, you have disadvantage on Dexterity saving throws, you can’t take reactions, and the only action you can take is an action to reassemble yourself.

Bone Pick

Your bony, skeletal hands can be used as simple tools. You gain proficiency with them, and can use them as Thieves Tools and Tinker's Tools. 

Real Backbone

Starting at 5th level, the necrotic energies that stitch you together in place of muscles keep you from from falling easily in battle. When you are reduced to 0 hit points and not killed outright, you can drop to 1 hit point instead. When this happens, you collapse into a pile of bones and are subject to all of the conditions of your False Appearance feature. You can use this feature a number of times equal to your Constitution modifier. This ability recharges after a long rest.

Ghastly Ambusher

Starting at 8th level, as a bonus action you can reassemble yourself and rise from a pile of bones surprising your enemies. If this is the first round of combat, any creature within 10 feet of you is considered automatically surprised. If this happens during combat, any creature within 10 feet of you that can see you must make a Wisdom saving throw equal to 8 + your proficiency bonus + your Charisma modifier.  On a failure, they are stunned until the end of your next turn. On a success, they are not stunned but are momentarily distracted and grant advantage to the next melee attack against them from your allies before the start of your next turn.

If a target is within 5 feet and not facing the you, they are unaware of your presence. This grants you advantage against them until the end of your next turn. If you hit this target unawares, treat it as a critical hit. 

You can use this feature a number of times equal to your Charisma modifier, and regain all uses after a long rest.

Evasion

Starting at 11th level, When you are subjected to an effect, such as a wizard's fireball or a dragonborn's breath weapon, that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.