The god of the sea in Greek mythology is Poseidon. He is one of the twelve Olympian deities and is often depicted with a trident, which he uses to control the ocean and create storms. Poseidon is also associated with earthquakes and horses, indicating his powerful dominion over various aspects of nature. His temperament can be both benevolent and vengeful, reflecting the unpredictable nature of the sea. Worship of Poseidon was crucial for sailors and coastal communities seeking favor and protection during their voyages.