Vengeful Blade (TP)

You brandish the weapon used in the spell's casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack's normal effects and then radiates a dark aura of energy until the start of your next turn. If the target makes an attack or casts a spell before then, the target takes 1d8 necrotic damage and the spell ends.

Cantrip Upgrade: This spell's damage increases when you reach certain levels. At 5th level, the melee attack deals an extra 1d8 necrotic damage to the target on a hit, and the damage the target takes for making an attack or casting a spell increases to 2d8. Both damage rolls increase by 1d8 at 11th level (2d8 and 3d8) and again at 17th level (3d8 and 4d8).