Ra-Seru Eggs are eggs that hatch into Ra-Seru. For them to hatch, they need the power of a healthy Genesis Tree. There were 10 Ra-Seru eggs in Legaia and were living inside Genesis Trees. Due to the crystal-like nature of the Ra-Serus, the eggs are often mistaken for jewels, which the player can use to his advantage by allowing Zalan of Jeremi appraise them to summon the Ra-Seru inside through their respective Talismans.
Due to the nature of the Rogues as Ra-Serus, the antagonists sought out to find the Genesis Trees' Ra-Serus to mimic the Mist producing abilities of the Rogues through them by using Ra-Serus and Ra-Seru Eggs to power their Mist Generators.