Who is Ibn Sayyad or Ibn Sa'id, and what is his true nature?

Ibn Sayyad, whose name was Safi, used to prognosticate, and it was said that he was the Dajjal. The Prophet, peace be upon him, tried to ascertain his true nature, so he visited him and asked him about visions and hid something from him. Ibn Sayyad answered him with "Al-Dukhkh." The Prophet did not deny that Ibn Sayyad was the Dajjal; rather, he said to 'Umar, "If he is him, you will not be empowered over him, and if he is not him, then there is no good for you in killing him." The Companions continued to believe that he was the Dajjal, to the extent that 'Umar and Jabir would swear by that in the presence of the Prophet without him denying it. Ibn Sayyad later tried to deny this accusation against him, arguing that the characteristics of the Dajjal mentioned by the Prophet did not apply to him, such as being a disbeliever, barren, and unable to enter Mecca and Medina, whereas he was a Muslim, had children, and had entered Mecca and Medina. The scholars differed in opinion regarding him being the Greater Dajjal; some said that he was one of the Dajjals but not the Greater Dajjal.