I have read that there are multiple brahmas; One each for a universe. Also heard that there are multiple vishnus too. So does that mean there are multiple shivas as well?
P.s :I know that the concept of parabrahm is that anything & everything is parabrahm itself
The concept of multiple universes is present in yoga vasistha. From the yoga vasistha, that is translated by Swami Venkatesananda -
O Rama, countless have been the universes that have come into being and that have been dissolved. In fact, even the countless universes that exist at this moment are impossible to conceive of. All this can immediately be realised in one’s own heart, for these universes are the creation of the desires that arise in the heart, like castles built in the air. (The story of Suka)
In the infinite consciousness, in every atom of it, universes come and go like particles of dust in a beam of sunlight that shines through a hole in the roof. These come and go like ripples on the ocean. (The story of Lila)
Millions of universes appear in the infinite consciousness like specks of dust in a beam of light streaming into a room through a hole in the roof. But, even as such specks of dust are not to be seen in the outside sunlight itself, the world is not seen in the supreme non-dual consciousness.
Now to answer the main question -
Of those countless universes, O Rama , in some there are only plants; some have Brahma, Vishnu and Rudra and others as the presiding deities, and some have none at all; in some there are only animals and birds; in some there is only an ocean; some are solid rocks; some are inhabited only by worms; some are pervaded by dense darkness; in some gods dwell; some are forever illumined. Some seem to be heading towards dissolution; some seem to be falling in space towards destruction. Since consciousness exists everywhere for ever, creation of these universes and their dissolution also goes on everywhere for ever. All these are held together by a mysterious omnipresent power. , everything exists in the one infinite consciousness; everything arises from it; it alone is everything. (The story of Lila).
Thus, trimurtis are not present in every universe.
Trimurtis are present in every Brahmanda.
This Lord, or Isvara, has three aspects: as Brahma He creates, as Vishnu He preserves, and as Siva He destroys. These three form as one Lord, or God, who is known by three different names according to His three functions. Since the Brahmandas are without number, so too are Brahmas, Vishnus, and Sivas without number. The Purana says: 'One maybe able to count the number of sands on the seashore, but one cannot count the number of the Brahmandas or the deities controlling them.
The Upanishads, Discussion of Brahman in the Upanishads, The Great Lord (Mahesvara), by Swami Nikhilananda
The constituents of creation beginning with mahat (intellect) and ending with Visesa [1] (earth) generate the cosmic egg, whence Brahma arose like a water-bubble.
Linga Purana I.3.28
[1] The group of seven beginning with mahat (intellect) and ending with visesa (bhutas) constitutes the Cosmic Egg which is material, though it derives its potency of consciousness (cetanata) from Purusa.
He alone is Rudra and Vishnu pervading the universe. These worlds are within that cosmic egg and this universe is within it.
Linga Purana I.3.29
The cosmic egg is externally enveloped by water ten times its magnitude. The water is externally enveloped by fire ten times its mass. The air is externally enveloped by the ether ten times its magnitude. The ether is enveloped by ego the cause of sound. The ego is enveloped by intellect and intellect is enveloped by Pradhana. They say that the coverings of the cosmic egg are seven [2]. There within is Brahma seated on the lotus. There are crores and crores of such eggs in existence.
Linga I.3.30-33
[2] The seven sheaths of the Cosmic Egg consist of intellect (mahat), ego (ahankara), and five subtle elements (tanmatras). (Vayu Purana 4.87, Kurma Purana I.4.46)
In all these cosmic eggs there are four-faced Brahmas, Vishnus and Rudras. They are all created by Pradhana after coming into contact with Siva.
Linga Purana I.3.34
