OVA
Description
Aquarius Dégel is the Gold Saint of the Aquarius Temple in the 18th-century Holy War, serving as the guardian of the eleventh house of the Zodiac. He is recognized within the Sanctuary as the wisest among Athena's Saints, a distinction that places him as the only individual besides the Great Pope capable of reading and interpreting the movements of the stars to foretell the future. His demeanor is consistently calm and polite, and he maintains his own personal library, reflecting his scholarly nature. He is also notably the only Saint depicted wearing glasses, a consequence of damage to his eyesight sustained during a past mission in France.

Dégel spent his childhood and received his training in the frozen region of Bluegrad, located in Siberia. He was trained by Krest, a former Aquarius Gold Saint, and also learned to read the stars from Garcia, the ruler of Bluegrad. It was during this time that he formed a deep and lasting friendship with Unity and his sister, Seraphina. Before departing Bluegrad to become a Saint, he and Unity made a solemn promise under the constellation Cygnus: Dégel would become a Knight of Athena while Unity would become Bluegrad’s ruler, together creating a bridge to connect their isolated homeland with the outside world. This promise, and his feelings for his friends, would become the central motivation for many of his later actions.

Dégel shares a particularly strong bond with Scorpio Kardia. The two became close after Dégel used his freezing powers to quell the burning fever caused by Kardia's heart condition, a task previously handled by Krest. Despite their opposing personalities, a deep mutual respect and friendship grew between them. Dégel is also highly respected by his fellow Gold Saints, including Shion, Dohko, and Defteros, with the latter being one of the few aware of the existence of Athena's secret guardian.

In the Holy War against Hades, Dégel is initially involved in strategic planning and observation. He is the one who advises the Pegasus Saint Tenma to seek training from the demon of Kanon Island. Later, Athena entrusts him with a critical mission: to journey to the submerged ruins of Atlantis and secure the Orichalcum, a crystal containing a portion of Poseidon's power, to aid in the assault on Hades's Lost Canvas. He invites his friend Kardia to accompany him on this dangerous quest.

Upon arriving in his homeland of Bluegrad, Dégel reunites with Unity, now the ruler of the land. Unity leads them to the entrance of Atlantis, where they are ambushed by the Specter Rhadamanthys and Pandora of Hades. Dégel initially fights while enraged over the apparent death of Unity, performing poorly until Scorpio Kardia reminds him that his freezing techniques require calm concentration to stop the movement of atoms, not destructive fury. He soon discovers Unity is alive but has become a Marine General of Poseidon, the Sea Dragon. Driven by a desperate wish to save Bluegrad from eternal cold, Unity had killed his own father and pledged himself to the sea god.

The conflict forces Dégel to confront his oldest friend. He resolves to stop Unity while vowing to keep their childhood promise alive. Using his ultimate technique, Aurora Execution, Dégel freezes the entire sea and collapses Poseidon's statue, freeing Unity from the god's control. However, Pandora intervenes and shatters the Orichalcum, causing Poseidon's unleashed power to possess Seraphina's body. To prevent the world from being destroyed by the sea god's awakening, Dégel makes the ultimate sacrifice. Reaching the absolute zero temperature his techniques are meant to achieve, he performs a massive Freezing Coffin, entombing himself, Seraphina, and all of Atlantis in an unbreakable prison of ice. In his final moments, he entrusts the fragments of the Orichalcum to the redeemed Unity to deliver to Athena, stating that he and Seraphina will watch over Bluegrad and bless his steps forever. His spirit later returns alongside the other deceased Gold Saints to deliver a final, decisive blow against Hades.

As a warrior who manipulates ice and cold, Dégel's power is directly tied to his emotional state. His techniques require immense concentration to lower temperatures and halt molecular movement. His signature attacks include Diamond Dust, a concentrated blast of ice and snow; Kol'tso, a ring of icy wind used to restrict an opponent's movement; and his ultimate technique, Aurora Execution, a devastating blast that simulates the aurora borealis and can reach temperatures near or precisely at absolute zero. His self-sacrifice to contain Poseidon is the moment he finally achieves true absolute zero, creating a Freezing Coffin of immense and permanent power.