I always thought the Illuminati was just another conspiracy theory until I saw this video and it made me re-spark my interest. Also I was confused when the shaytaan said that was his son but he could have meant it metaphorically because iblees made a whole club awaiting for his arrival.
You're right, it is metaphorical it seems... however, for those of you who are familiar with the story of the samiri during the exodus, you will know that he too was the dajjal of his time, and some scholars seem to propagate that the samiri may have been a jinn in human form and not a human. So. We can't rule out that the dajjal could be a jinn...