Basics
The basic elements are Lef (Healing), Ig (Flame), Aqu (Water), Teo (Wind), Tou (Lightning), Soa (Light) and Sere (Dark). These elements have a delicate balance in the Treasure of the Rudras universe. Look to the right of this paragraph:
Fire is weak against Water and Water is weak against fire. For example, if you're wearing fire-aligned armor then you will be weak against water attacks. But if you're wearing water-aligned armor then you will be weak against fire attacks. Get the idea? You don't have to memorize that table because it's also in the game's equip menu to let you know what elements your characters are strong/weak against once they equip a certain weapon/armor/accessory. And then there's Nihi (Void) and Pra (Earth); these elements have no weaknesses.