Who is venus? What it his story?
Assuming that you are talking about Roman mythology, Venus is the goddess associated with reproduction, beauty, and love. She is also known as Aphrodite which is the Hellenic (Greek) version of her name as the Roman mythology became penetrated by Greek influence.
Acc. to her story, she was born in primal Chaos. A story goes that:
She was called Eurynome, which means "wide wandering one". She was born of primal Chaos, dancing on the water. Eurynome transformed the North Wind into a serpent named Ophion. The serpent coiled himself around her, impregnated her and she gave birth to the Cosmic Egg. Ophion wrapped himself around the egg seven times and stayed until it hatched Creation.
She was one of the causative factors of the Trojan War, as she competed against other goddesses to see who was the most beautiful. Since Zeus wanted to stay out of it, he asked a young Shepperd, Paris, to choose. All three competitors, Athena, Juno, and Aphrodite bribed him with gifts. Aphrodite offered him a beautiful woman if he picked her. He did, and Aphrodite gave him a golden apple which led directly to the fair woman that she promised him. Only problem was that the woman was already married. Her name was Helen, and her husband was none other than King Melenaus.