"Say: whoever is an enemy to Jibreel - for he brings down the (revelation) to your heart by Allah’s will. . . " [2:97]
Jibreel A.S is also called as Rooh-ul-Ameen
He is the Keeper of Hell, as Allah says in Holy Qur'an :
"They [the people in Hell] will cry: ‘O Malik! Would that your Lord put an end to us!’" [43:77]
The task of munkar and nakeer is to question the deceased in the grave.
The questions which these angels put to the deceased in his grave are: Who is your Lord? What is your religion? Who is this man who was sent among you?
These were two angels who are known to be behind bringing magic to this world
They angels taught magics to people after the death of the Sulayman A.S in order for people to be able to neutralize the magics of evil magicians.But people misused what they learnt
Allah says in Qur'an : and such things as came down at Babylon to the angels Haroot and Maroot . . ." [2:102]