You can manipulate the balance between life and death, granting you the following benefits.
Pull of Death
Once per turn, when you deal damage to a creature that's missing any Hit Points by casting a spell or by hitting with an attack roll, that creature takes an extra 1d4 Necrotic damage. This extra damage increases to 1d6 when you reach Cleric level 11.
Return to Life
You can cast Spare the Dying as a Bonus Action.
Additionally, when you would normally roll one or more dice to restore Hit Points to a creature at 0 Hit Points with a spell or Channel Divinity, don't roll those dice for the healing; instead, use the highest number possible for each die. For example, instead of restoring 2d4 Hit Points to a creature at 0 Hit Points with a spell, you restore 8.