Poseidon

Just like Zeus Poseidon is a son of Kronos and Rea. According to one sources he was the second son of Kronos. But, there are also informational sources according to which Poseidon is a first son of Kronos. It is a matter of argument nowadays, and, according to mythology, it was a matter of argument between Zeus and Poseidon. Poseidon considered himself a god just as powerful and mighty like Zeus. And so he was jealous for Zeus authority.
He was the one who colluded with Hera in order to drive Zeus away the throne and was sentenced to exile together with Apollo. Together with Apollo he built defensive walls of Troy. They were not paid for their work and so Poseidon send an ocean monster that greatly damaged property of one who offended Poseidon. He was so powerful that it was enough for him to touch a vessel and turn it into a mountain.
That is how he did with those who made blind his son. After the vessel was turned into mountain it was deepen into the see as reef. Once the Kronos was driven away his sons started division of the world. They couldn't decide who will be the main god and so they tossed. And the toss showed that Poseidon will be a god of seas and oceans and all the water in the earth.
He was depicted as a strong and brawny man with trident in his arms. Image of Poseidon was provided with long hair and beard. His hair was blue just like the water in the ocean and he was always riding long-manned horses. Though, Poseidon was second-mighty god he believed that is better than Zeus and that he is the one to be supreme god of Olympus.