What is Satan? To whom does it come and what does he instill into humans?
Shaytan (in Arabic) is an entity analogous to Satan in Christianity. Satan means secret, malicious force, and evil spirit. The name Satan especially has become the name of unseen souls and evil forces. When it is said, Iblis (name given to the primary devil in Islam; Iblis was a Jinn, a creature made of smokeless fire), first individual, who is the forefather of this kind recur to the mind at first. The entity of satan like humans announced to humans with these Quranic verses, When they meet those who believe, they declare (hypocritically), We believe; but when they are alone in secret with their (apparently human) satans (to whom they hasten in need to renew their unbelief and their pledge to them for fear of losing their support), they say: "Assuredly we are with you; we only mock (those others)." (Al-Baqarah Surah, 2:14), And thus it is that (as a dimension of human earthly life taking place according to Our eternal Will embracing human free will, and according to the wisdom in sending the Religion) We have set against every Prophet a hostile opposition from among the satans of humankind and jinn, whispering and suggesting to one another specious words, by way of delusion. Yet had your Lord willed (and compelled everybody to behave in the way He wills), they would not do it. So leave them alone with what they have been fabricating. And the hearts of those who do not believe in the Hereafter incline towards it (their deluding speech) and take pleasure in it, and they continue perpetrating the evils that they have long been perpetrating. (Al-Anam Surah, 6:112, 113)
Satan mostly comes to the ones, who think that they are perfect, and he makes their sinful acts alluring to them (Al-Anfal Surah, 8:48); negators and unbelievers, that is to say hypocrites, while disbelieving (in God), he/she says (to humans) as if he/she believes (Al-Hashr Surah, 59:16; Al-Baqarah Surah, 2:24); who eat what is unlawful and impure (Al-Baqarah Surah, 2:168); who hope help from him in their wrongful deeds (Al-Anfal Surah, 8:48); who do not seek refuge in God from Satan, soothsayers, fortune tellers, and mediums (Al-Hijr Surah, 15:17, 18); who boldly commit sins and overindulge in lies (Ash-Shuara Surah, 26:21, 22). In addition, he mostly comes to the ones, who worship to the natural entities such as sun, moon, and stars (An-Naml Surah, 27:74); who oppose God and His Messenger, and forget remembrance of God (Who created and nurture him) (Al-Mujadilah Surah, 58:19, 20); who lack in sincerity and faithfulness (Al-Hijr Surah, 15:39, 40); and so many of those who are rebellious, deniers, and disobeyers.
He persuades them to go on their everyday and night deviances, makes them negligence, and stops them to turn from their deviances, and never let them go until they die.
And Satan will say, when the matter is decided: "Surely God promised you something that was bound to come true; I too promised but I failed you. And I had no power over you, except that I appealed to you, and you answered me. So do not blame me, but blame yourselves. I cannot respond to your cry for help, nor can you respond to my cry for help. I reject your associating me as a partner with God (in belief or worship) in the past." Surely, for the wrongdoers (who have wronged and ruined themselves by denying God or associating partners with Him) there is a painful punishment. (Ibrahim Surah, 14:22)