A unique sacrifical dark healer class idea

[LukeTheNuke123]

I personally have always loved the concept of a healer who doesn't heal by imparting magical power that causes the bodies of their targets to restore themselves but instead through the absorption or release of life energies whether that be them giving their own life energy to heal their targets wounds or taking their targets ailments upon themselves with I think this would work better as a monk probably but also could be done conceivably as a cleric but with heavy restrictions on the spells you can use making it so you can only use necromancy which doesn't include cure wounds and healing word as well as all the other healing spells but with a caveat that you don't have spell slots and instead to cast any spell requires either your life force or the target's life force meaning you're necrotic damage spells aren't necessarily necrotic damage spells in the same vein as a normal arms of Hadar for example but instead are more akin to you sapping the life force of your target with at low levels you only restore half of the damage dealt and at higher levels that percentage goes up and up basically meaning what limits you from casting spells further or casting spells as stronger levels is the amount of health you have to give with that also applies to damage spells in the vein that if you miss the target with say for example inflict wounds, the only life force there is to drain is your own meaning you will take the damage that your opponent would have taken instead meaning each time you will roll the damage first and then the attack will go off and either they get hit and they take the damage and you heal or they dodge and you take the damage and get no healing. All in all it's honestly just feels like a sort of healer that I'm still to the state curious as to why we haven't seen because I'd love to see a healer who takes the blindness upon themselves before then in an attack giving it to the enemy or takes a curse from their friend onto themselves but then immediately can force it on the curse caster who put it on their friend in the first place making it a super high risk versus reward sort of playstyle with perhaps also an additional 1D4 healing per turn just to help make sure you don't pretty much guaranteed kill yourself every other f*#@ing fight