The descriptive phrase refers primarily to Necrozma in its Ultra Necrozma form. This Pokmon, characterized by its immense power, achieves this state by absorbing either Solgaleo or Lunala and then utilizing Z-Power. A visual representation of this transformation involves the emanation of intensely bright light, resembling the fiery appearance of a star, thus creating the imagery of celestial illumination.
This transformation is significant within the Pokmon lore as it represents a pinnacle of power and a crucial plot point. The character embodies not just brute strength, but also a desperate struggle to regain lost light. This concept adds depth to the narrative and provides a compelling reason for its actions, furthering the thematic exploration of light and darkness prevalent in the related games and media. Historically, the introduction of this being marked a shift towards increasingly complex character narratives within the franchise.