:salam2:
In Surah Al Kahf, ayah 50, Allah azza wa jal says: And [mention] when We said to the angels, "Prostrate to Adam," and they prostrated, except for Iblees, He was of the Jinn and departed from [disobeyed] the command of His Lord....
Therefore, Iblees was indeed a Jinn, he was not an angel (or a fallen angel as some might say)
In Ibn Kathir's Tafsir of Surah Al-Baqarah pertaining to the story of Iblees, its says:
Honoring Adam when the Angels prostrated before Him
This Ayah mentions the great honor that Allah granted Adam, and Allah reminded Adam's offspring of this fact. Allah commanded the angels to prostrate before Adam, as this Ayah and many Hadiths testify, such as the Hadith about the intercession that we discussed. There is a Hadith about the supplication of Musa, "O my Lord! Show me Adam who caused us and himself to be thrown out of Paradise.'' When Musa met Adam, he said to him, "Are you Adam whom Allah created with His Own Hands, blew life into and commanded the angels to prostrate before'' Iblis was among Those ordered to prostrate before Adam, although He was not an Angel
When Allah commanded the angels to prostrate before Adam, Iblis was included in this command. Although Iblis was not an angel, he was trying - and pretending - to imitate the angels' behavior and deeds, and this is why he was also included in the command to the angels to prostrate before Adam. Satan was criticized for defying that command, as we will explain with detail, Allah willing, when we mention the Tafsir of Allah's statement,
[إِلاَّ إِبْلِيسَ كَانَ مِنَ الْجِنِّ فَفَسَقَ عَنْ أَمْرِ رَبِّهِ]
(Except Iblis (Satan). He was one of the Jinn; he disobeyed the command of his Lord.) (18:50)
Similarly, Muhammad bin Ishaq reported that Ibn `Abbas said, "Before he undertook the path of sin, Iblis was with the angels and was called `Azazil.' He was among the residents of the earth and was one of the most active worshippers and knowledgeable persons among the angels. This fact caused him to be arrogant. Iblis was from a genus called Jinn.''
(And they prostrated except Iblis (Shaytan), he refused and was proud and was one of the disbelievers (disobedient to Allah).)
"Iblis, the enemy of Allah, envied Adam because Allah honored Adam. He said, `I was created from fire, and he was created from clay.' Therefore, the first error ever committed was arrogance, for the enemy of Allah was too arrogant to prostrate before Adam.'' I - Ibn Kathir - say, the following is recorded in the Sahih,
«لَا يَدْخُلُ الْجَنَّةَ مَنْ كَانَ فِي قَلْبِهِ مِثْقَالُ حَبَّةٍ مِنْ خَرْدَلٍ مِنْ كِبْر»
(No person who has the weight of a mustard seed of arrogance in his heart shall enter Paradise.)
Iblis had disbelief, arrogance, and rebellion, all of which caused him to be expelled from the holy presence of Allah, and His mercy.
So according to these ayat and the tafsir, there is no mention of any being higher or more evil than Iblees that convinced him to disobey Allah by not prostrating to Adam (AS) rather it was out of envy and arrogance. Also Allah (SWT) tells us this in Surah Al-A'raf, ayat 12 and 13:
12: [Allah] said, "What prevented you from prostrating when I commanded you?" [Shaytaan] said, "I am better than him [Adam]. You created me from fire and created him from clay [earth].
13. [Allah] said, "Descend from it [Paradise], for it is not for you to be arrogant therein. So get out; indeed, you are of the debased.
Therefore, only Shaytaan's arrogance and his envy for Adam caused him not to prostrate to Adam and disobey Allah (SWT)
I pray to Allah azza wa jal that this answer your question and the other questions posed. Wa Allahu Alam.
:salam2: