Adar's Cremation

Roaring blue flames flare out towards a a point you can see within range. forming a line 80 feet long and 15 feet wide. Each creature in the line must a Dexterity saving throw. A target takes 4d12 fire damage on a failed save, or half as much damage on a successful one, and are not ignited.

The fire spreads around corners. It ignites creatures or a flammable objects. The target takes (1d8) fire damage at the start of each of its turns. While ignited, the creature cannot be healed by any means. The blue flame cannot be extinguished except by magic or water. A creature that dies to the spell's initial or DOT damage is reduced to ash, as are any nonmetallic and nonmagical possessions on the body.