Unified slash

Choose one willing creature within the range range to expend 1st or 2nd level spellslot as their reaction. Their magic fuses with your blade enabling you to release a devastating cut of  black energy. Make a ranged spell attack against creature in range. On a hit, the target takes weapon damage as ussualy. Hit or miss, each creature within 5 feet around the target (him included) has to succed on a dexterity saving throw as the slash erupts  dealing 2d6 magical slashing damage per slot used.

At Higher Levels. The max spellslot used increases when you reach 5th level (1-3 lvl spell slot), 11th level (1-4), and 17th level (1-5).