Dark Domain

The dark domain came to exist in the ancient times, when life was flourishing. Clerics tried to maintain it, but some did not think it was enough. Out of the darkness came the dark domain, originally created to steal the lives of the evil and feed it to the good. Some abused this, others made sure it was not.

Cursed Healing

When casting a healing spell, you can spend your bonus action to deal necrotic damage equal to your wisdom modifier to one target within 30 feet

Death Magic

At first level, when casting a necromancy spell or cantrip you can add your wisdom modifier to the damage roll.
On a critical hit, you regain HP equal to twice the level of the spell

Channel Divinity: Absorb Health

At second level, you can use your channel divinity as a bonus action after a necromancy spell and add half the damage to a health pool. This pools maximum capacity is your level x 10.
On your turn you can use your action to heal either yourself or others around you. You may only heal one person at a time.

Shadow Strike

once on each of your turns when you hit a creature with a weapon attack, you can cause the attack to deal an extra 1d8 necrotic damage to the target. When you reach 14th level, the extra damage increases to 2d8

Life sharing

At 17th level, you can set up a bond between your allies and you. By using your concentration, you can connect your life forces and you will not die unless you are all brought to 1 hit point or your concentration is broken