Necromancer
This sorcerer’s power first manifested after they were exposed to the cosmic energy of death, inuring them against death and allowing them to sense, harness, and manipulate this power.
Essence of Death – At 1st level, a necromancer learns the cantrips wither and withering pulse in addition to the cantrips they learn from the Spellcasting feature.
In addition, a necromancer is resistant to fatigue damage and adds their proficiency bonus to death saves and saving throws made to resist afflictions. If they already add their proficiency bonus to those saves, it is doubled.
However, the process of undeath has begun to take hold: whenever they would regain hit points from an Invocation (Life) spell, they regain the minimum number possible and can’t cast ranked spells until the end of their next turn.
Lifeblood – Starting at 1st level, a necromancer can draw power from living creatures that they kill. Whenever they reduce a living creature to 0 hit points, they gain temporary hit points equal to their Power + the creature’s hit dice. If they still have these temporary hit points when they spend a hit die to regain hit points, they lose them and regain an equal number of hit points.
Sense Death – Starting at 1st level, a necromancer can sense the presence of any corpse or undead creature within 10 yards, and can use an action to focus on one corpse or undead creature, making a Wisdom (Insight) check to discern information about it.
Result 5+ – The necromancer knows the location of the corpse or undead creature and knows the power echelon that the corpse was while living or the undead is currently.
Result 11+ – The necromancer knows the exact level that the corpse was while living or the undead is currently. They also know how and when the corpse died or what type of undead the creature is.
Result 17+ – The necromancer gains a vision of the corpse’s last moments, lasting from a minute before their death to a minute after. They also discern the abilities of the undead creature.
Mantle of Death – Starting at 2nd level, a necromancer can use a bonus action and spend a Sorcery Point to surge with necrotic energy, creating a mantle of death for 1 minute. This effect ends early if they are incapacitated or use a bonus action to end it early.
While the mantle is active, the conduit’s eyes turn black, any nonmagical plants within 3 yards of them start to wilt, and any nonmagical food within 3 yards of them starts to spoil. This evident power allows them to add their Charisma modifier to Constitution (Intimidation) checks.
In addition, the necromancer adds their Charisma modifier to the damage of Invocation (Death) spells and any living creature that starts their turn within 3 yards of them takes necrotic damage equal to their Power + their Charisma modifier.
Furthermore, living creatures within 3 yards of the necromancer regain the minimum number of hit points possible from spells, features, and hit dice.
Lastly, a necromancer is considered undead while their mantle of death is active. They can’t be targeted as a living creature, are rattled while exposed to sunlight, and take 1d10 fire damage if they end their turn exposed to sunlight.
One Foot in the Grave – At 6th level, a necromancer becomes resistant to necrotic damage. If their Mantle of Death is active, they are instead immune to fatigue damage and necrotic damage.
In addition, whenever a necromancer of this level takes necrotic damage, they can spend a Sorcery Point to become immune to that damage. If they do, they can also spend a hit die to regain hit points equal to the die roll + their Constitution modifier + their Charisma modifier.
Undeath – At 10th level, a necromancer is no longer living, but rather undead. They no longer suffer any ill effects due to deprivation or exposure and automatically stabilize when reduced to 0 hit points.
Their Mantle of Death is always active, and they can theoretically exist forever in this state. They will never die of old age and will never again gain any penalties associated with aging.