The Sun of Solaria is one of the three magic stars of the Magic Dimension that function as Solaria's suns, and is therefore its planet's source of life without which Solaria is destined for darkness. The king of Solaria cannot live without both of its planet's suns and will fatally fall ill if the suns loses their light energy. While the three Suns of Solaria are located in space and can be seen in Solaria's skies at day, the essence of both the First and Second Sun of Solaria are housed in the Steeple of the Sun inside the Royal Palace of Solaria. The alignment of the three Suns of Solaria is a rare occurrence and it is a cause of celebration for the citizens of Solaria.
The Sun of Solaria is a bright yellow star and its power stored in the Steeple of the Sun takes the form of a bright ball of yellow light.
In "Valtor's Mark," Valtor pays a visit to Cassandra and Chimera and offers to grant the two astonishing powers to cast charms and spells and the chance to make all their dreams come true in return for bathing in the light of the Sun of Solaria. Cassandra, tempted by Valtor's offer of being able to rule over Radius, and for Chimera to become the new princess of the Sun and the Moon, leads Valtor to the Steeple of the Sun. Cassandra opens the doors of the steeple and presents Valtor with the sun. He feels its energy flowing through him. After replenishing his power, he grants his accomplices new powers with the Mark of Valtor and transports out of the steeple in the light of the sun.
In "The Fairy and the Beast," Valtor monologues that thanks to the Sun of Solaria, he is strong again. The Trix enter and Darcy asks if the sunbath worked, which prompts Valtor to make the space around him ignite, showcasing his new power.
In "The Pillar of Light," Luna enters the Steeple of the Sun in a panic as the light of the Sun of Solaria is eclipsed. Finding Radius, she asks him if he is alright, but he is displeased that she did not knock. She expresses her concern for him due to the strange darkness plaguing Solaria, but he assures her that the Second Sun of Solaria will compensate for it. Luna once again voices her concerns, but Radius rejects her. Just then, the sun shines blindingly and begins to flicker, weakening Radius as Luna screams out for help. Later, Luna tells Stella about Radius' condition and that the darkness has affected both the suns of Solaria, and that the king cannot live without them.
In "The Eclipse," the Second Sun of Solaria shines again in the Steeple of the Sun as the eclipse of the Sun of Solaria ends.
In "Saving Paradise Bay," the two suns are in the sky of Solaria as Luna intercedes for the alliance against Tritannus, asking the Second Sun of Solaria to shine for the alliance, and through her, send its light to them. Meanwhile, the light of the second sun strengthens the alliance.