Shaytaan (Iblis) was of the Jinn, not a "fallen angel"

The Noble Quran says in V. 18:50 that Satan was of the Jinn and so he rebelled against Allah Almighty by disobeying His command of prostrating before Adam. As Muslims, we believe only this.

"And (remember) when We said unto the angels: Fall prostrate before Adam, and they fell prostrate, all save Iblis. He was of the Jinn, so he rebelled against his Lord's command. Will you choose him and his seed for your protecting friends instead of Me, when they are an enemy unto you? Calamitous is the exchange for evil doers!" 18:50 Surah Al-Kahf

Because Shaytaan was of the Jinn, therefore, like humans, he could choose his path of conduct - whether to be obedient or disobedient to the commands of Allah Almighty. And Shaytaan chose to be disobedient.

The idea of Satan being a 'fallen angel' is NOT from the Noble Quran. In the Noble Quran there's no such concept of any angel being a 'fallen' one. This story of Satan being a 'fallen angel' comes from the altered Bible, as usual, from versions such as Jude, Matthew, Isaiah etc.

Satan, who belonged to the Jinn, couldn't possibly have been an angel prior to being a Jinn. That just doesn't make sense. The Bible folks started this gossip based on some pagan myth. In the older versions of the altered Bible, the term "Lucifer" was often used for the devil. "Lucifer" which is a Latin word is supposed to mean a "light bearer. It's the most inappropriate name for Satan because Satan or devil is NOT a "light bearer." Much the opposite. Satan (or the devil) is a spreader of darkness through his sins. It is also said that in these older versions of the changed Bible, the term 'lucifer' was given to the devil in fictional stories.

The concept of 'fallen angels' from a pagan myth was named (or based) upon the title "morning star." This myth was later transferred to Satan by the Christians, giving Satan the name of "Lucifer" meaning "light bearer," similar to the pagan title of "morning star."

Some Christians say that "morning star" refers to the meaning of being destined to fall from the sky.

However, this entire concept of 'fallen angel' is a myth and gossip with NO references in the Noble Quran. Therefore, we are NOT to accept it. We only accept as much as the Noble Quran says, that Satan was of the Jinn, so he rebelled against Allah's commands and thus became an outcast, the biggest enemy of Allah and of the believers.