From a satsang with Paramacharya of SWAHA, H.H. Pundit Hardeo Persad
According to the Bhagwat Mahaa Puraan, the Lord is the infinite, Nirguna Brahm, without qualities. He is without beginning, middle or end. He is beyond the known and unknown. That Supreme Lord can be called Param Shiva, Param Atma or Param Brahm. That state is unconditioned and without attributes, unmanifest. When the Ultimate, Absolute Reality takes on attributes, it is known as Saguna Brahm. The Bhagavad Gita states that the Lord manifests from age to age to restore righteousness and to save devotees. There are several types of manifestations or Avataars that the Divine may assume.
The Bhagwat Mahaa Puraan states that the first manifestation is Guna Avataar. There are 3 gunas or modes of existence: sattvic, rajasic and tamasic prakriti. Lord Vishnu is the infinite manifested as sattva. Bramha represents rajas. Shivaji represents tamas prakriti. These 3 gunas also exist on each of the planes of existence, bhu, bhuvah, swah (physical, astral, causal). In the heavenly, causal plane, Sattva represents lightness and brightness; Rajas represents creativity, whereas in the gross plane, it represents materialism; and tamas represents non-differentiation, whereas in the gross plane, it represents lethargy. On the earthly plane, the three gunas are represented in Ramaayan by Kaushilya, Kaikeyi and Sumitra: sattva, rajas and tamas, respectively, based on their intentions and actions. In the psychological or astral places, the three gunas are represented by Vibheeshun, sattva, the epitome of spirituality and dutifulness; Ravan, passionate and angry, represents the rajasic state and Kumbhkarna, representing sluggishness and inertia, is tamasic prakriti.
There are also the Vyuha Avataars. In Krishna katha, the four Vyuha Avataars are Krishna Bhagavan, Balram, Anirudha and Pradyumna. In the Ramaayan, they are Shree Raam, Lakshman, Bharat and Shatrughan. The Leela Avataars are the 24 manifestations of Lord Vishnu: 10 are major and 14 are minor manifestations. The Ans Avataar, is a particle of the Divine manifestation, that is, Ishwar ans avinaashi. This includes each of us, embodied souls, as we are all sparks of divinity. Eventually we must realise that we are Aham Brahmasmi, one with the Divine. There are also Kalaa Avataars, which include the great sages such as Chaitanya Mahaaprabhu, who would often be totally absorbed in the divine power of Bhagavan Shree Krishna.