Ayya Vaikundar (Tamil: அய்யா வைகுண்டர்), according to Akilattirattu Ammanai, a scripture of the Ayyavazhi, was a Manu (father, sovereign) avatar (the incarnation of a deity) of Narayana. As per the Ayyavazhi mythology the body in which Ayya Vaikundar incarnated is that of Mudisoodum Perumal.
He is referred to as Sampooranathevan, a deva, in the religious book Akilam. However the exact date of birth of Mudisoodum Perumal was unknown. The Akilattirattu Ammanai mention that when the body of Mudisoodum Perumal is taken into the sea he was 24 years old. In that sense it was predicted as 1809 and in history there are different views about the year of birth. But some historians opinions it as 1810 while others follow the view of Akilam. Any way the exact day and month of birth was unknown. According to Akilam, the avatar of Vaikundar took place in Three phase. The first stage of Avatar was the born dead child (birth of the Body). Next, immediately the soul of Sampooranathevan was installed into the body, along with the Spirit of Narayana kept in Parvatha Ucchi Malai after the completion of the Krishna Avatar. This was the second stage of the Avatar. Then in the sea (during the 24th year in 1833), the soul of Sampooranathevan was granted moksha, unified to the Ultimate Soul. Now, the Spirit of Narayana along with the Ultimate Soul (Paramatma) incarnated in the body of a human being (Muthukutty). This is the third stage of Avatar and from then he was called Ayya Vaikundar.