Astrid's Ignis Mortem

You draw on your life to create a line of roaring flame 60 feet long and 5 feet wide emanates from you in a direction you choose that both burns and drains the souls of those it hits. You take 5d10 necrotic damage that cannot be reduced in any way. Each creature in the line must make a Dexterity saving throw. A creature takes fire damage equal to the damage dealt as well as the same amount of damage as necrotic damage a failed save, or half as much damage on a successful one.

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