The nameless’s death bolt

You call upon the ancient power of the nameless sticking your hands forward releasing a straight line of necromancy in front of you make a ranged spell attack against the target of this spell on a hit the target takes 6d8 necrotic damage and make a wisdom saving throw or be frightened of you for 1 minute the target makes the saving throw regardless to the attack hitting 

a higher levels: the damage increases by 1d8 for every spell slot you use above 3rd