Vishnu

Saantaakaarm Bhujga Sayanam
Padmanaabhaam Suresam
Visvaadhaaram Gagana Sadrisam
Megha Varnam Subha Angam
Lakshmee Kaantam Kamala Nayanam
Yoghibir Dhyaana Gamyam
Vande Vishnum Bhava Bhaya Haram
Sarva Lokaika Naatham.

The Master of the universe, Lord Vishnu who is always in peace, who has a serpent bed, he is the one from whose navel blooms the lotus. He is a authority on Gods, whose form consists entire universe, he pervades all over the sky, the hue of cloud and a beauty. He is Lord of Lakshmi, Lotus eyed. He is always liked by yogi’s and can be reached by meditating on him.
He is the destroyer of all fears prevailing in this world.

Yes he is the supreme pursha, who is always available and do welfare for all. He is Lord of world, He is endless.
He is Shri Maha Vishnu.
Taking mentions from Narad Puran, Sanakji a Sage mentioned Bharamrishi Narad about the creation of universe by Lord Narayana (Vishnu).

He Said O Bhramrishi Lord Narayan is Immortal, neverending, who is present everwhere (omnipresent), who is defectless. He is the only one who has occupied this whole universe by his creatures.

Enlighted the Lord of Universe Shri Maha Vishnu has choosen different- different charteristics and qualities created three identities to start this universe. Firstly he created Prajapati Bhrama to create this universe.

Secondly he created Rudra Lord Shiva for destroying the life.

Thirdly he created Vishnu as survivor of this Universe.

But the Supreme Lord is only one whether people call him Vishnu, Brhama or Shiva.
He the lord Narayana is the only authority behind the working of this life system. Every creature has Vishnu in it, every life has its part(Ansh).
He is the only occupying the all designations in this kingdom of deities. He is the Essence, heis the conscious , he the only joy.

It is belived that Vishnu has ten incarnations (Dus Avtars)

The First Avtar is known as Matsya Avtar , second is Kurma Avtar, third is Varaha Avtar, fourth is Narsingha Avtar, fifth is Vamana Avatara, sixth is Parsuram Avtar, Seventh is Shri Ram Chandra Avtar, the eight is Krishna Avtar, the ninth Avtar is Balram, the tenth Avtar is Budha which is mentioned in Bhagvata Purana.