The Flower of Life, a gift from Karas, is where the elves received their power from before the Divine War. It was broken during the War, causing massive destruction and deaths. Afterward the elves build the Core and split into two factions, the Wind Elves and the High Elves. Only High Elves remain.
Later, during the Divine War that pitted god against god, the Flower of Life was accidentally damaged and began leaking uncontrolled magic—a bit like a nuclear reactor melting down. To keep the devastation from spreading, the elves transferred the flower’s magic into a sorcerous lattice they call the Core. All that dangerous power is now contained within the Core—under the control of an elf who sacrifices a normal life to become one with the Core and control it."