Bloodflame Blade

You touch the weapon used in this spell's casting as you draw blood from yourself and invoke an incantation. For the spell's duration, the weapon you touch is enchanted with Bloodflame: cursed blood which sets a creature's essence ablaze with its touch. The enchanted weapon emits Bright Light in a 10-foot radius and Dim Light 10 feet beyond that, and attacks made with it deal an extra 1d4 Fire damage.

Once per turn when a creature is hit with the enchanted weapon, you can force the target to make a Constitution Saving Throw. On a failure, the target takes 2d10 Necrotic damage and gains one level of Exhaustion. On a success, the target takes half as much damage but suffers no other effects. A creature that has any levels of Exhaustion caused by this spell makes a Constitution Saving Throw at the end of each of its turns, reducing its Exhaustion level by 1 on a success. Any levels of Exhaustion caused by this spell are removed when the spell ends.

Constructs and Undead are immune to damage caused by this spell, and automatically succeed on the Saving Throw.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the Necrotic damage dealt by this spell's Saving Throw increases by 1d10 for each spell slot level above 4th.