Ridhwan is the name of the angel mentioned in the Islamic scriptures. He is in charge or keeper of Paradise.
One must believe that the angels are from the creation of Allah; no one knows their exact number except Him. They are from the unseen world. Allah created them to worship and obey Him. They carry out all of Allah’s orders, from administration, observation, guarding and protecting the universe as well its creatures, all according to Allah’s Will and Order.
Allah has charged the angels with specific duties, and they do what they are commanded. Allah says: "They fear their Lord above them, and they do what they are commanded." (Quran Surah 16:50)
The angels are not partners, associates, or rivals with Allah, nor are they His children; but one must still respect and love them. Allah says: "And they say: ‘The Most Beneficent (Allah) has begotten a child [from the angels].’ Far removed is He from every imperfection! They (the angels) are but honored slaves. They speak not until He has spoken, and [then] they act on His Command." (Quran Surah 21:26-27)
They spend their time worshipping and obeying Allah, glorifying Him and praising Him. Allah says: "They (i.e. the angels) glorify His praises night and day, (and) without slackening (to do so)." (Quran Surah 21:20)
The angels were created from light. The Prophetﷺsaid: 'The angels were created from light, the Jinn were created from a smokeless flame of fire, and Adam was created from what was described to you (black dry clay).' Sahih Muslim 2996
Although they were created from light, they cannot be seen. Allah has given them the ability to change their appearance in order to be seen and witnessed. Allah informs us that Jibreel (Gabriel) came to Maryam (Mary) in the form of a man: "She placed a screen [to screen herself] from them; then We sent to her Our Rooh (Jibreel), and he appeared before her in the form of a man in all respects. * She said: ‘Verily! I seek refuge with the Most Beneficent (Allah) from you, if you do fear Allah.’ * [The angel] said: ‘I am only a Messenger from your Lord [to announce] to you the gift of a righteous son." (Quran Surah 19:17-19)
Anas b. Malik(R) reported: The Messenger of Allah (ﷺ) said: I will come to the gate of Paradise on the Day of Resurrection. and would seek its opening. and the keeper would say: Who are you? I would say: Muhammad. He would then say: It is for you that I have been ordered, and not to open it for anyone before you. Sahih Muslim 197 
A Muslim must believe specifically in all the angels named and/or described in the Qur'an and the ahadith: