The door was locked and bolted, but it swung silently open and Xaltotun stood before them, calm, tranquil, stroking his patriarchal beard; but the lambent lights of Hell flickered in his eyes.
“I have taught you too much,” he said calmly, pointing a finger like an index of doom at Orastes. And before any could move, he had cast a handful of dust on the floor near the feet of the priest, who stood like a man turned to marble. It flamed, smoldered; a blue serpentine of smoke rose and swayed upward about Orastes in a slender spiral. And when it had arisen above his shoulders it curled about his neck with a whipping suddenness like the stroke of a snake. Orastes’ scream was choked to a gurgle. His hands flew to his neck, his eyes were distended, his tongue protruded. The smoke was like a blue rope about his neck; then it faded and was gone, and Orastes slumped to the floor a dead man.
-- Hour of the Dragon, Robert E. Howard
So you want to pump up the magic-user class?
How about a 1st level Death Spell!
Herein I am using Labyrinth Lord stats and descriptions…
Think about it. Magic Missile is a 1st level spell. It has a range of 150’, deals 1d6+1 hit points of damage (average 4.5), and always hits its target. That’s powerful enough to kill most 0-level Normal Men and even powerful enough to kill most 1st level characters and 1 HD monsters.
Death Spell is a 6th level spell (can be used as early as 11th level). It has a range of 240’ and kills 4d8 HD of creatures of 8 HD or less (essentially, Name Level characters are immune), though all the targets get a saving throw versus Death.
Poisons… all characters of all levels fear poison, as all characters of all levels can still be slain by the same simple poison…
So let’s just up the ante a little bit, and give everyone a reason to fear magic-users… because no one fears low-level magic-users once they have reached 5th level (no more sleep effects on you, right).
Try this on for size…
Range: 40’ plus 20’ per level
When this spell is cast a ray of black, coruscating energy emits from the caster’s finger, directed at a single target within range. The target must then make a saving throw versus Death; failure indicates instant death. If the target is of a higher level or hit dice than the level of the caster, the target gets a +4 bonus to their saving throw. If the saving throw succeeds, and the target is of higher level or hit dice, nothing happens. If the target is of equal or lower level or hit dice, the target suffers 1d6 points of damage plus 1 point of damage per level of the caster.
The appearance of the spell can vary from caster to caster, though once a magic-user learns the spell it will always have the same appearance (d10):
1. Arc of Black Lightning
2. Sickly Purple Ray
3. Coiling Indigo Tendril of Smoke
4. Flash of Blue Flames
5. Whip of Green Energy
6. Staccato Bursts of Yellow Beams
7. Scintillating Orange Beam
8. Scorching Red Ray
9. Blinding White Flash of Light
If you want to limit the use of this spell, have each casting require the use of a material component, such as black lotus, or demon ichor, or some other such material rare and expensive (say, 1,000 gp per casting). Or perhaps the magic-user must craft a special wand to use as a focus, costing 1,000 gp; without the wand, the caster cannot cast the spell.
Bellatrix laughed, the same exhilarated laugh her cousin Sirius had given as he toppled backward through the veil, and suddenly Harry knew what was going to happen before it did.
Molly’s curse soared beneath Bellatrix’s outstretched arm and hit her squarely in the chest, directly over her heart.
Bellatrix’s gloating smile froze, her eyes seemed to bulge: For the tiniest space of time she knew what had happened, and then she toppled, and the watching crowd roared, and Voldemort screamed.
-- Harry Potter and the Deathly Hallows, J.K. Rowling