When Kubera went to Kailasam once to have a darshan of Lord Shiva, he found Him with Goddess Parvathi. Kubera was stunned to see the splendour and beauty of Goddess Parvathi. He felt sorry that he had not worshipped such a fine goddess for so long and one of his eyes shut itself.
Goddess Parvathi got angry that Kubera was winking at Her, and looking at Her with evil intention. She made his eye burst. Kubera lost sight in one eye and was also cursed that he would always look ugly. Lord Kubera pleaded with Lord Siva to forgive him and explained that he had not seen the Goddess with any evil intention. Lord Siva left the choice to His consort. Goddess Parvathi forgave Kubera and let the eye grow back, but it was smaller than the other one.
So one eye of Kubera is smaller than the other. Kubera was rewarded by Lord Siva with the post of being one of the guards of the eight directions - the North. The Goddess made him the lord of wealth and material.
As the God of wealth and material, his responsibilities are to distribute them while creating wealth is with Goddess Lakshmi. Kubera is mostly painted with his family and seen showering gold coins and navaratnas.
Performing pooja to Lord Kubera is believed to enrich one's life. To have a wealthy
and comfortable life, one has to perform Sri Lakshmi Kubera Pooja.
Lord Balaji or Venkateswara at Thirupathi is said to have Borrowed money form Kubera for his marrige and he is still paying the interest on the loan amount. Hence it would seem that lord Venkateswara will be in protection during the ashadmasa
"Om Yakshyaya Kuberaya Vaishravanaaya Dhanadhanyadi Padayeh
Dhana-Dhanya Samreeddhing Me Dehi Dapaya Swaha"
Meaning: Kubera, the lord of yakshas, bless us with wealth and prosperity.