The Seed of Light has the power to drive away any kind of Shadow Monster one time. They need light to be activated.
The Seed of Light are small oval-shaped seeds that have a gold shimmer. Once sprouted, the seeds become green plants with triangles along the stems and an orb of green light on the top.
In "Princess Amentia," Aisha throws the Seeds of Light down in the cave she is in to drive away the monsters, but they do not take root as they need light to do so. Then, Stella enters the cave and emits enough light for the seeds to take root and disintegrate the monsters.