The Battle of Atarisundri was a battle between The Gnome Empire from the north of Kandarin and goblin tribes from the south.
At some point in the fourth age the elves living in Kandarin went west, leaving a lot of land open for conquest. The gnome and goblin forces eventually met, resulting in the Battle of Atarisundri. The gnomes were brave but the goblins were far larger in numbers. However the gnome king, Healthorg, and one of his advisors, Glouphrie the Untrusted, had devised a plan to trick the larger army facing them.
Using his control over light magicks, Glouphrie conjured an illusion of several giant tortoises, knowing the goblins would be scared of them. Upon seeing this illusion the goblins fled in fear, resulting in victory for the gnomes.