Different identities from same source
"Om namo bhagavate Vasudevayah"
In the material conception of life, we see different types of living being. We identify them with different names, someone as demigod, someone as human being, as dog, as cat, etc. All these different identities are a material vision which arises due to material conception of life, our material understanding. This is not the true vision.
In reality the material bodies of all living being or even non living materials arise from single source, and that is the Prakriti ( material nature) .
This fact is very clearly explained by Lord Shri Krishna in Shrimad Bhagvat Gita. Please have look at this shloka.
ch13:sh31
yada bhuta-prthag-bhavam eka-stham anupasyati
tata eva ca vistaram brahma sampadyate tada
When one sees different identities and different material bodies arise from single source material nature, one attains Brahman.
The shloka above very clearly defines that all material bodies arise from single source, the material nature.
All living beings come into existence by the combination by Ksetra(body) which is part of this Prakrit(material nature) and the Purusha, the soul.
Ch13:Sh27
yavat sanjayate kincit sattvam sthavara-jangamam
ksetra-ksetrajna-samyogat tad viddhi bharatarsabha
O Best of Bharatas! Know that whatever, the movable and unmovable, is born, it comes into existence by the combination of Ksetra( the Field) and Ksetrajna(the knower of the Field).
This body starts in this material word due to inter-transformation of elements. This body remains here in this world even after death. For the time when Purusha(Atma) resides in body, living being is considered alive.The moment soul leaves this body the living body is considered dead
Different identity of a living being is due to the different way of attachment of a soul with this material nature. The type of actions being performed by one soul living in one body causes it to take birth in another body and so have other identity. The soul remains same but then it changes the identity.
Both Purusha and Prakriti in turn are formed of Supreme Personality of Godhead Shri Krishna. So finally everything in this universe is formed of that Supreme himself.
I have found a lot of confusion in people about one v/s many. We should all understand that source of everything is that supreme himself. This material nature and lives in it have been manifested to have different identities.
Hope this discussion will help you remove the confusion about one and many.
"Shri Hari Om Tat Sat"