Brahman is absolute. It has no avatars.
However, Brahman exists in two forms.
1. Saguna Brahman: The state of activity at which we don't feel our body
2. Nirguna Brahman: The state of rest at which we don't feel our body.
The two are not two avatars of Brahman because in the Brahman state we don't feel end of one activity and beginning of the next activity.