Hazrat Mahdi (as) is the peacock (adornment) of the Paradise.

(Bihar al-Anwar, Vol 51, p. 105)

 

According to Abdullah bin Abbas' account, related in Daylami's Firdaws, the Messenger of Allah (saas) said, "The Mahdi is a handsome young man from the people of paradise."
(Al-Uqayli An-Najm al-saqib fi Bayan Anna al-Mahdi min Awladi Ali Ibn Abi Talib Ale't-Temam wa al-qamal)

 

..It is narrated from Anas ibn Malik (ra) that: I heard the Messenger of Allah (saas) say: We are the senior ones of the people of Paradise, the children of Abdulmuttalib. Me, Hamza, Ali, Jaffar, Hasan, Hussein and the Mahdi.

(Sunan Ibn Majah, 10/349)