Tournesoul

Tournesoul is a form attained with the process of combining two individual beings who share the blood of the Asmius Family into one being, resulting in a form that creates unimaginably legendary power. The two beings must maintain a peaceful mindset by expelling negative thoughts, sins, and emotions out, leaving only pureness in one's heart. It is stated that this legendary fusion has only been attained once (due to there only being one female Asmius relative whose shares the Goddess's blood per generation), and can only be attained once per life cycle. Tournesouling is used to represent a fusion of both sun and moon energies, which when combined, creates pure light that can never be expelled in any way.

Origin
In Final Fantasy XVI, Tournesoul was founded, according to Gilgamesh, by Delia Asmius, the first queen of Olion. She, who shared the blood of the Goddess, used the power of light to heal and repel the world from natural evil. When a monstrous beast was created by the negativities of the conflicting gods who wished to dethrone her, Delia attained Tournesoul by merging with her own brother and used it to defeat the monster. When this form was seen by people, it was stated that shafts of light enveloped the universe, radiating rapidly while banishing the darkness from the universe. Energies from the sun and moon clashed together on Delia and her brother's Tournesoul form.

The result of Tournesouling was too powerful, and as a result, her brother was killed in the process due to his body becoming unable to attain the form. Delia's offspring would later create the entire Asmius lineage, where no one was ever seen using Tournasoul due to them unable to hold enough power.

Usages
Tournesoul is attained by June Asmius and Jill Sevoka when they battle Halla Cordus and Firia in Frozen Ticonderoga. June instructs Jill to repel the negative sins she performed as an Edelian Commander and to focus primarily on her future with Drai, Mari, and uncovering her family. She repels Halla's attacks, and by doing so, buys Jill enough time to attain her Tournesoul form. June and Jill merge together in forms of black and white, combining and forming a fusion which completely overpowers Halla and Firia. They battle and break the barriers of time, and eventually eradicates Firia by separating him from Halla and eliminates him for good with the power of light.