Lugh can best be described as the Celtic Power of excellence, reputed to be not only the inventor and patron of the arts, but also an expert in such diverse fields as sorcery, history, craftsmanship of all sorts, story telling, and heroism. Lugh, whose name means “The Shining One” is the most widely worshipped of the Pantheon, with numerous monuments throughout Celtic regions where followers prayed to him for guidance in any of his many areas of expertise. Known to be a late comer to the pantheon, Lugh is often found in the company of Rosmerta, a goddess of wealth and material possessions. He can control endeavors in the arts and crafts with which he is familiar, and he can control or influence all forms of travel and commerce. He can also turn day to night or vice versa at will. Beyond these pursuits, however, Lugh is a formidable warrior, armed with a great spear and a sling.
A wanderer of the lands of his worshippers, consorting with the various goddesses of the lands that he meets, Lugh is a self-confident god, eager to keep his hand in mundane affairs. He keeps an eye out for fair play in human matters, stepping in with his avatar to affect the outcome of endeavors within his own expertise.
Source: Legends & Lore (2nd ed.)