What is the authenticity of the hadith: "Die, O Angel of Death," and what is the response to those who say there is more than one angel of death?

The Angel of Death is one, and he has assistants, as indicated by Allah's saying: "Our messengers caused him to die" and "until, when Our messengers come to them to take their souls." Imam Al-Tabari holds that the act of causing death is attributed to the Angel of Death, even if it is carried out by his assistants, because it is done under his command. Similarly, Ibn Abbas, Mujahid, and Al-Rabi' ibn Anas are of the opinion that the Angel of Death has assistants from among the angels.