The god who appears in Snorri and the poems to be the ruler of the sea is Aegir. He seems to be a personification of the ocean and its mighty strength for good or evil towards men. His name is related to the word for water, and he has much in common with the Greek god Poseidon. The Vikings called the River Eider "Aegir's Door", while in their poetry the "jaws of Aegir" devoured lost ships at sea. The ocean has inevitably figured as the greedy destroyer in the poetry of sea-going folk. "The sea has snapped the ties of my kindred", says Egill in the great poem of mourning, the Sonatorrek, composed after his young son was lost at sea. "Could I have avenged my cause with the sword, the Ale-Brewer would be no more". It was perhaps to a god of this kind, relentlessly demanding victims, that Saxon pirates in the fifth century were accustomed to sacrifice a tenth of the captives by lot.
An Old English poetic name for the sea, garsecg, means literally "spear-man", and suggests the image of a fierce warrior, recalling Poseidon with his trident. The weapon of the Norse couple, Aegir and Ran, seems to have been a net, with which Ran would entrap seafarers. A folk-belief quoted in one of the Icelandic sagas is that when people were drowned they were thought to have gone to Ran, and if they appeared at their own funeral feasts, it was a sign that she had given them a good welcome. In a late sage, Fridhjof's Saga, it is said to have been a lucky thing to have gold on one's person if lost at sea. The hero went so far to distribute small pieces of gold among his men when they were caught in a storm, so they should not go empty handed into Ran's hall if they were drowned. The idea of the hospitality of Aegir and Ran, who were so anxius to throng their underwater realm with the hosts of the dead, may be compared with that of the god of battle. It is by no means inconsistent with the power to destroy.
When however Egill refers to Aegir as the Ale-Brewer, and the poems make reference to the gods gathering for a banquet in the halls of Aegir, we may discern a different aspect of the god of the sea. In Celtic mythology, cauldrons of plenty are sometimes represented as coming from the land-beneath-the-waves. The banquest at which Loki made his scandalous attacks on gods and goddesses in Lokasenna was in Aegir's hall, and it was to obtain a suitable cauldron for the mead at another of Aegir's feasts that Thor went down to the sea to visit Hymir. Snorri in Skaldskarmal identifies Aegir with Gymir and Hlr who lived on Hlesey. Gymir, it may be noticed, is the name of the monstruous and terrible giant of the underworld, the father of the beautiful Gerd wooed by Freyr. Hymir, who seems to be a sea-giant, has a link with the gods, for he is said in Hymiskvidha to me the father of Tyr.
Aegir's place indeed should perhaps be among the giants rather than the gods. He is said to have had nine daughters, and it is generally assumed that these are the waves of the sea. They are called by such names as Gjolp, "howler", and Greip, "grasper". These however are typical giantess names as well, and nine giantesses are said to have been the mothers of the god Heimdall, the most puzzling of the dwellers in Asgard. Certain passages in the poems seem to imply that Heimdall was born of the sea, and that these nine daughters of Aegir were his foster-mothers.
Davidson, Gods and Myths of Northern Europe. Pelican Books, 1964. Pages 128- 130.