Aid of the Damned

You call forth the power of dark magic within you and encase the weapon of an ally with magical energy to enhance their power and ensure the enemy receives maximum suffering. When an ally attacks you can cast this spell to let them deal an additional 1d8 necrotic damage if the attack hits. Should they fail the attack roll the user of the weapon takes (1d6 damage + the number of your corruption points) hit points of damage.

When using a Higher-Level Spell Slot. The damage increased by 1d8 for each spell slot level above 1. The damage your ally receives is increased by 1d6 for every spell slot level above 1.