Cruel Sun

You make a small to medium ball of pure fire at the point of one of your fingers. the size of the ball depends on the casters level, growing as the casters level grows.
make a ranged spell attack. on hit, the target takes 3d8 radiant damage
if target is fiend, it also has disadvantage on attack rolls against you until the end of your next turn.

This spell does not increase in damage if casted at higher levels but instead grows in damage at certain levels.
3d8 radiant damage from levels 1 - 5
4d8 radiant damage from levels 6 - 10
5d8 radiant damage from levels 11 - 15
6d8 radiant damage from levels 16 - 20