I think Iblis is the main leader, who instructs and guides all the shaytaans (who are below him in rank). Iblis is under the Dajaal in rank. Every time the shaytaan that are under iblis do something really bad, they are rewarded. Basically the shaytaan are bad jinns. The only thing that makes them the same is the fact that they are EVIL and are our enemies!
Iblis is the name of the Jinn that was arrogant and refused his Lord's order to bow before Adam. He became the outcast and now known as shaytan or the devil. A shaytan is a being that is evil and does evil, plural form is shayateen. They can be jinns or human. From what I have read, dhajjal is a human that will be the biggest fitna or trial for mankind. Before him will appear 30 smaller dhajjals (false messiahs). Iblis and dhajjal don't rank or compare with each other. One will come only for a short time as a trial for mankind and will perish at the hand of Jesus pbuh, and the other has been given respite till end of time to do as he wishes.
I asked my Imam about it and he said that Iblis is a creature made out of fire and Shaytaan is just a "force of disobedience." He compared it to what some psychologists call "id." Now it makes sense when we read the hadith:
Narrated Said bin Al-Musaiyab: Abu Huraira said, "I heard Allah's Apostle saying, 'There is none born among the off-spring of Adam, but Satan touches it. A child therefore, cries loudly at the time of birth because of the touch of Satan, except Mary and her child." Then Abu Huraira recited: "And I seek refuge with You for her and for her offspring from the outcast Satan" (3.36)
Human beings are obviously a product of lust. Lust is an "id" or shaytaan-ic force. Isa (as) was born without a father, thus no man touched our beloved Mariam (as). Therefore we can conclude that (unlike what the Christians claim:"Mohammad admits that Jesus is God") our Prophet (pbuh) meant the lust aspect of shaytaan?
I'm no scholar, and I could be 100% wrong. But could this be the reason?
Iblis literally means 'thoroughly disappointed; utterly in despair'. In Islamic terminology the word denotes the jinn who, in defiance of God's command, refused to obey and to yoke himself to the service of Adam and his progeny and asked God to allow him a term when he might mislead and tempt mankind to evil and error. He is also called al-Shaytan(Satan)
In fact Satan (or Iblis) is not an abstract, impersonal force. Like human beings he is possessed of a specific personality. Moreover, one should not make the mistake of considering Satan an angel. Elsewhere the Qur'an itself clearly states that he was a jinn and jinn, as we know, are an independent species, distinct from the angels. (See Qur'An 18: 50.)
You can not reduce Iblis to the id factor of the ego model. The id is critical for survival. It is the survival motif.
The seducer of mankind knows that he creates an illusion for mankind. His deception is the destruction of mankind. He is playing a game he knows he is going to lose. He wants company.
I don't want to play a semantics game but lust is taking it a little too far. That is the reason it is considered a sin. It is wanting too much and not being able to wait. Hence, marriage is important in Islam. We have hadith on that. When the Prophet, swas, was aroused he went to one of his wives. Deep stuff to break down and think about.