Conclave of the Gravetender.

Rangers that tend to the cemeteries and final places of rest in the world are Gravetenders. These solemn caretakers are wardens of the circle of life, and traverse such oft-ignored yet hallowed grounds with grim purpose. And, like the dead returning to soil, Gravetenders offer their vitality in exchange for power and survival. They stand as silent sentinels, vigilant against the encroachment of desecration and undeath, and defend the memories of persons, beasts, and more to ensure their voices are never forgotten to the ravages of time.

Level 3 Feature:

Gravetender Magic.

Starting at 3rd level, you learn an additional spell when you reach certain levels in this class, as shown in the Gravetender Spells table. The spell counts as a ranger spell for you, but it doesn't count against the number of ranger spells you know.

Touch of the Departed.

Also at 3rd level, you gain the ability to connect with the dead and preserve the lives of those teetering on the edge. You learn the Spare the Dying cantrip, which counts as a ranger spell for you, and undead are considered to be a favoured enemy for you, if they weren't already.
In addition, you can use an action to touch a corpse to learn its relative age when it died (in years), as well as the kind of creature it is, including its species or race if it's a humanoid. You can use this feature a number of times equal to your Intelligence or Wisdom modifier (a minimum of once). You regain all expended uses of it whenever you finish a long rest.
When you reach 7th level in this class, you also learn the name of a corpse you touch in this way, as well as how it died; you don't learn the details of the death itself, merely the general nature of it (such as falling rocks or a stab wound to the back). If the corpse was Small or larger, you also regain two spent Hit Dice.

Grave Strikes.

Starting at 3rd level, your attacks can more easily drive a foe to its grave. Once per turn when you hit a creature with a weapon attack, you can deal an extra 1d4 damage of the weapon's type to the target. This extra damage increases by 1d4 if the creature is missing any of its hit points.
When you reach 11th level in this class, these extra damage dice become d6s.

Level 7 Feature:

Vitality Master.

At 7th level, whenever you roll a Hit Die, you can roll the die twice and take the higher result. In addition, you regain any spent Hit Dice whenever you finish a long rest.

Level 11 Feature:

Reaper.

Starting at 11th level, when you deal damage to a creature using your Grave Strikes feature, it marks that creature for the grave. The mark lasts until the start of your next turn. If a Small or larger creature dies while marked in this way, you also regain one expended Hit Die.
Whenever you roll the damage dice from your Grave Strikes feature, you can choose to spend a Hit Die to usher the target to their demise. When you do, roll the Hit Die and add your Constitution modifier to the result; this die isn't included when determining the extra damage for a critical hit. You then add the total to the damage of the attack, which gains the following benefits:
-You can change the attack's damage type to necrotic.
-You learn if the target has more or fewer than half its hit points remaining.
-If you rolled a 19 on the attack roll, the attack scores a critical hit.

Level 15 Feature:

Undying Warden.

By 15th level, any critical hit against you becomes a normal hit. Furthermore, when you're hit by an attack, you can use your reaction to spend a Hit Die and roll it. The result of the attack roll is reduced by an amount equal to the number rolled on the Hit Die; this doesn't include your Constitution modifier. You can decide to spend an additional Hit Die after each roll.