Order of the Deathless

Author's note: Thanks for trying out my subclass! Feel free to leave some comments or advice on this subclass in order to balance or buff certain aspects of it, as I have few chances to play test it myself. Thanks!

The order of the deathless have always been intertwined with the idea of death. Originally a group stemming from the Order of the Ghostslayers, those of the deathless focused specifically on the moments just prior to death, the driving forces that allow hunters to overcome their obstacles when all seems lost. Those of the order of the Deathless draw power from approaching death, thriving off of the pain, and overcoming it. Because of this, many who are part of this order have or will become insane, due to the constant pain they suffer in their quest for power in combating their enemies. Nonetheless, they throw themselves at danger, strengthening they're wills through combat and pain.

Bleeding Deception

Due to being in constant pain from the many scars associated with being a blood hunter, you have learned how to persuade others into helping your weak, hurting soul. Beginning when you choose this order, when you are below one fourth of your current maximum hit points, you have advantage on persuasion and deception checks.

Undying Vitality

You have learned how to bolster your stamina when near death, using the adrenaline given through fighting to strengthen your resolve. At 3rd level, when you are below one half of your current maximum hit points and take the attack action with a weapon that has your crimson rite applied to it, you gain temporary hit points equal to the total crimson rite damage dealt. You continue to gain temporary hit points with successive strikes, and lose all of the temporary hit points at the start of your next turn. 

At 11th level, you can convert the stamina boost gained from your adrenaline into energy. At the start of your next turn, if you have more than 0 hit points, you can heal yourself by an amount equal to half of your remaining temporary hit points.

Painful Rites

You thrive off of the pain suffered by activating your crimson rites, and in response can momentarily strengthen their power at the cost of pain. At 7th level, when you deal damage with a weapon that has your crimson rite applied to it, you can take damage equal to the crimson rite damage to double the crimson rite damage dealt. You may perform this a number of times equal to your wisdom modifier(Minimum of once). The uses of painful rites recharge after a short rest or long rest.

Deathless Calling

Approaching death is not the end for you, as you let the pain course through your veins, re-invigorating your spirit momentarily. At 11th level, you are able to remain conscious for a brief period, using the pain of being near death to drive you further and pushing onward. If you drop to 0 hit points, you can choose to suffer a death saving throw failure to remain conscious. You gain temporary hit points equal to half of the damage dealt to you, during which your hit points remain at 0, and you take turns as normal following initiative order. Should you run out of temporary hit points while your hit points are at 0, you immediately fall unconscious. You still remain conscious even if using this ability causes you to suffer a third death saving throw failure, in which you immediately die after you run out of temporary hit points.You can use this ability once at 11th level, and twice at 18th level. 

Adaptive Resistance

Having become accustomed to pain on a daily basis, you have learned how to strengthen your body's natural resistances to certain attacks, particularly when you are waning in energy. At 15th level, when you fall below one half of your current maximum hit points, you can immediately choose to gain resistance to one type of damage. When you fall below one fourth of your current maximum hit points, you can either gain immunity to the damage type chosen or gain another resistance. You lose this resistance(s) when your current hit points are greater than one half of your current maximum hit points.

Sacrifical Amplification

You draw upon the many wounds that have been afflicted on you throughout your life, re-opening the many wounds received to numb out incoming pain. You then reciprocate this pain onto incoming foes. At 18th level, as a bonus action you can reduce your current hit points by an amount equal to three fourths of your current hit point maximum to be immune to the next 3 sources of damage (excluding self-inflicted damage). You can choose which three sources of damage you mitigate. After 3 sources of damage occur, your next weapon attack imbued with your crimson rite deals additional bonus crimson rite damage equal to half of the total damage received over the three sources damage. You may use this feature twice per long rest, as long as you are not reduced to zero hit points by activating this ability.