Brilliant Blade

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails. On a hit, the target suffers the attack's normal effects, and it and all hostile creatures within five feet of it take radiant damage equal to your spellcasting ability modifier.

At 5th level, the melee attack deals an extra 1d6 radiant damage to the target, and the radiant damage to the adjacent creatures increases to 1d6 + your spellcasting ability modifier. Both damage rolls increase by 1d6 at 11th level and 17th level.