In Chapter 2, Duster is sent out to Osohe Castle by Wess to obtain the egg since he sensed a great danger approaching the village and felt the need to keep the egg safe. As Duster, who is later joined by Wess and Kumatora, finally reaches the top floor where the egg is located, he is confronted by the Pigmask Army, who are also after the Egg of Light. Startled, Kumatora grabs the egg in a hurry, only to set off a trapdoor which they fall through and land in a body of water, only to be ambushed by the Oh-So-Snake.
The power of the egg is shown in Chapter 5, when amnesiac Duster, believing he is the DCMC bassist, Lucky, reclaims the Egg from the Forlorn Junk Heap and regains his identity as Duster. This is the only time the egg is used, despite how important Wess makes it seem. The secrets it contains includes The People of the White Ship, which Leder talks about in Chapter 8.