Maalik
In Islamic belief, Maalik () denotes an angel in Hell/Purgatory () who administrates the Hellfire, assisted by 19 mysterious guards (Q) known as Zabaniyya (). In the Qur'an, Maalik is mentioned in  as the chief of angels of hell. The earliest codices offer various alternative spellings of this word including , meaning "angel", instead of a proper name. In Qur'an 
In  and the following, the Qur'an describes Maalik telling the people in hell that they must remain there: 

 points out, that the punishments are carried out by God's command: "O believers! Protect yourselves and your families from a Fire whose fuel is people and stones, overseen by formidable and severe angels, who never disobey whatever Allah orders—always doing as commanded.". In Hadith 

According to Islamic tradition, Muhammad met the angel Maalik during his heavenly journey. Therefore, Muhammad arrived in heaven and all the angels greeted him with a smile except Maalik. When Muhammad asked Jibra'il, why he remains taciturn therefore, he reveals Maalik as the guardian of Hell who never smiles. After that, Muhammad asked him to show Hell and Maalik opened its gates, showing him a glimpse of suffering for the inmates. According to Abbasid jurist Ibn Qutaybah, who also known as Al-Qutb, the number of the fingers of Maalik were equal to the sinners who will be thrown into hell. Ibn Qutaybah also narrated each fingers of Maalik were so hot that if it touched the sky, that finger will cause the sky to melt. al-Suyuti also quoted that since his creation which spans thousand years before hell created, Maalik strength always grow perennially each day passed. See also
 List of angels in theology
 Zabaniyah
 Malik
 Moloch
 Ridwan
 Yama

References

Angels in Islam
Individual angels
Jahannam