Vero's Fiery Guillotine

You create a fiery guillotine and target one creature within range. The target must succeed on a Strength saving throw or take 6d10 fire damage, or half as much on a sucess. If the targetted creature has attacked you within your last turn, it has disadvantage on this saving throw. If this spell drops the target(s) to 0 hit points, they are killed instantly. 

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the fire damage increases by 1d10 for each slot level above 5th. Also, when you cast this spell using a spell slot above 6th level or higher, you may target one additional creature for each slot level above 5th. You may not target the same creature twice with this spell in one turn.