Vaiśravaṇa (Sanskrit वैश्रवण) or Vessavaṇa (Pāli वेस्सवण) is the name of the chief of the Four Heavenly Kings and an important person in Buddhism.

Name 
The name Vaiśravaṇa comes from the Sanskrit viśravaṇa which means "Great Fame".

Vaiśravaṇa is also known as Kubera in Sanskrit or Kuvera in Pāli.

Character 
The character of Vaiśravaṇa is set up on the Hindu god Kubera, but although the Buddhist and Hindu deities share some characteristics, both of them have different functions and myths.

He is often shown with a yellow face. He carries an umbrella as a sign of his power. He is also sometimes shown with a mongoose, often shown spitting out jewels. The mongoose is the enemy of the snake, which is a symbol of greed or hatred; the spitting out of jewels shows generosity.

Vaiśravaṇa in Theravāda tradition 
In the Pāli writings of the Theravāda Buddhist tradition, Vaiśravaṇa is called Vessavaṇa. Vessavaṇa is one of the Four Great Kings, each one of which rules over a direction. Vessavaṇa's direction is the northern quarter of the world.

Vessavaṇa has the name "Kuvera" from a name he had from a past life as a rich mill-owner, who gave all the money he got from one of his seven mills to charity, and gave aid to the poor for 20,000 years.

As with all the Buddhist deities, Vessavaṇa is properly the name of a person who has the god inside him rather than a permanent individual. Each Vessavaṇa is a human, and when he dies, he will be replaced by a new Vessavaṇa. Like other beings of the Cātummahārājika world, his lifespan is 90,000 years, but other sources say nine million years.

When the Buddha was born, Vessavaṇa became his follower. He often brought the Buddha and his followers messages from the gods and other humans, and protected them.

Vaiśravaṇa in Japan 
In Japan, Bishamonten (毘沙門天), or just Bishamon (毘沙門) is thought of as a god of war or warriors who wears armor, and a punisher of people who do evil things, a view that is very strange when compared with the more peaceful Buddhist king described above. Bishamon is shown holding a spear in one hand and a small pagoda in the other hand. The Pagoda symbolises the divine treasure house, which holds things that he guards and gives away. In Japanese folklore, he is one of the Japanese Seven Lucky Gods.

Vaiśravaṇa in Tibet 
In Tibet, Vaiśravaṇa is known to be a worldly protector of the Dharma. He is also known as the King of the North. As guardian of the north, he is often shown on temple wall paintings outside the main door. He is also a god of wealth. Vaiśravaṇa is sometimes shown carrying a citron, the fruit of the jambhara tree. The fruit helps pick him out from depictions of Kuvera.

Vaiśravaṇa in popular culture 
 A character called "Uesugi Kenshin" in the Playstation 2 game Samurai Warriors prays to Bishamon a lot for strength. He also gains the title "Bishamonten Avatar" at one point.
 In the video game series Onimusha: Warlords a Bishamon statue is seen. The Bishamon Sword is also the best weapon in the game.
 In Atlus' video game series Megami Tensei, Bishamon is put into the Kishin clan which includes the protectors of various things.
 In the PC game Touhou: Unidentified Fantastic Object, in the fifth stage, the heroine fights Shou, a tiger Youkai who earned the title "Disciple of Vaiśravaṇa" because she is the Avatar of Bishamonten. Shou's theme is called "The Tiger Patterned Vaisravana" since she is the Avatar of Bishamonten, as stated above.

Related pages
 Four Heavenly Kings
 Seven Lucky Gods

References 
 Dictionary of Pali Proper Names
 Wrathful Guardians of Buddhism - Aesthetics and Mythology
 Deities in Buddhism

Notes 

Buddhist gods and goddesses
Japanese deities