Quem esfaqueou Frodo?

Foi o Rei Bruxo que esfaqueou Frodo.

There were five tall figures: two standing on the lip of the dell, three advancing. In their white faces burned keen and merciless eyes; under their mantles were long grey robes; upon their grey hairs were helms of silver;... Two of the figures halted. The third was taller than the others: his hair was long and gleaming and on his helm was a crown. In one hand he held a long sword, and in the other a knife; both the knife and the hand that held it glowed with a pale light. He sprang forward and bore down on Frodo.

At that moment Frodo threw himself forward on the ground, and he heard himself crying aloud: O Elbereth! Gilthoniel! At the same time he struck at the feet of his enemy. A shrill cry rang out in the night; and he felt a pain like a dart of poisoned ice pierce his left shoulder.

Tolkien, J.R.R.. The Fellowship of the Ring: Being the First Part of The Lord of the Rings (pp. 195-196). Houghton Mifflin Harcourt. Kindle Edition.

but all blades perish that pierce that dreadful King. -Aragorn to Frodo about the incident.

For even the Wise might fear to withstand the Nine, when they are gathered together under their fell chieftain. A great king and sorcerer he was of old, and now he wields a deadly fear. -Gandalf on the nine.

Se você está certo em aceitar a palavra dos filmes, Gandalf afirma claramente que foi o Rei Bruxo

Gandalf: Sauron has yet to reveal his deadliest servant. The one who would lead Mordor's armies in war. The one they say no living man can kill: the Witch-King of Angmar. You've met him before. He stabbed Frodo on Weathertop.

Era o Rei Bruxo (Provavelmente)

Two of the figures halted. The third was taller than the others: his hair was long and gleaming and on his helm was a crown. In one hand he held a long sword, and in the other a knife; both the knife and the hand that held it glowed with a pale light. He sprang forward and bore down on Frodo.

At that moment Frodo threw himself forward on the ground, and he heard himself crying aloud: O Elbereth! Gilthoniel! At the same time he struck at the feet of his enemy. A shrill cry rang out in the night; and he felt a pain like a dart of poisoned ice pierce his left shoulder.

Teoricamente, poderia ter sido de outro Nazgûl (não vemos a greve real), mas a implicação é muito clara.

Na adaptação cinematográfica de Peter Jackson , o evento é mais claro

IN THE TWILIGHT WORLD:

Frodo finds himself in the weird twilight world...he looks upon the Ringwraiths, now visible in their TRUE APPEARANCE: Five Ghouls dressed in long Grey robes, with white hair, and Pallid, ruthless faces. THE WITCH KING extends a haggard hand towards Frodo, reaching for the ring on his finger. Frodo's trembling hand extends forward as if by the pull of the ring...he slides to the ground, unable to pull his hand away. The witch king snarls and springs forward. He stabs at Frodo with a wicked dagger! Frodo winces as the tip of the dagger sinks into his shoulder. Suddenly, Strider charges at the RINGWRAITHS, wielding his sword in one hand, a flaming torch in the other. He moves in slow motion, visible through a sea of mist. Frodo sinks to the ground. Behind him is a faint image of a Ringwraith fleeing, his head engulfed in flames. With draining strength, Frodo manages to pull the ring off his finger...

_{^{LOTR: Fellowship of the Ring - Original Script}}

E novamente na adaptação de Ralph Bakshi de O Senhor dos Anéis , ele definitivamente foi esfaqueado por um personagem mais tarde identificado como o Rei Bruxo.

Era o senhor dos Nazgûl (anteriormente conhecido como o Rei Bruxo de Angmar), ou pelo menos parece ter sido o mais poderoso cavaleiro negro presente.

Two of the figures halted. The third was taller than the others: his hair was long and gleaming and on his helm was a crown. In one hand he held a long sword, and in the other a knife; both the knife and the hand that held it glowed with a pale light. He sprang forward and bore down on Frodo.

Tolkien parecia ter algo sobre altura como um indicador de poder. (Éomer era o mais alto dos cavaleiros que abordaram Aragorn, Legolas e Gimli.) O modo como a figura com a espada é apontada sugere strongmente que era o senhor Nazgûl.