Phantasos

•Grim Fantasia: When attacking, Phantasos pronounces the name of the technique, deploying his cosmos around him, which expands to cover the area where his opponent is located, thus creating an environment resembling outer space. Within this environment, the opponent cannot move their body or use their cosmos freely. Taking advantage of this, Phantasos approaches the opponent and places his extended hand, surrounded by his cosmos, on their torso. Then, with that same hand, he extracts their soul, encapsulating it in a small sphere of energy. In this state, the victim begins to experience the vision of the dream they most yearn for. Phantasos can take the souls he has captured to the region of the dream world he governs, Phantasia, where the spheres containing the souls of his opponents remain floating. Furthermore, by taking one of the spheres in his hands, he can see the dreams and desires of his victims.

After his brothers Ikelos and Morpheus were also defeated, Oneiros confronts Tenma and El Cid. In the midst of this fight, Oneiros summons the souls of Phantasos, Ikelos, and Morpheus. In this way, the souls of these gods also possess Oneiros' body, bestowing upon him greater power and granting him immortality, allowing him to regenerate any wounds he receives. Since El Cid, Tenma, Yuzuriha, and Yato have no way to defeat this enemy, Athena and Sisyphus must interfere in the fight. Sisyphus fires the Golden Arrow of Sagittarius, covered in Athena's cosmos. As the arrow heads towards Oneiros, El Cid leaps and, using his Excalibur, splits the arrow into four parts, thus hitting the souls of the four gods simultaneously, inflicting a mortal wound that leads to their destruction. At that moment, Hypnos orders Oneiros to at least try to take Pegasus with him. Therefore, Oneiros concentrates his cosmos in his body and heads towards Tenma to explode with him, but El Cid interferes and pushes Oneiros' body towards the heavens, where both disappear in the god's explosion. This is how the souls of Phantasos and his brothers disappear forever.

Phantasos, along with his three brothers, is summoned by Hypnos, who orders them to find the Saint of Pegasus to imprison him in the Dream World and thus prevent him from interfering in the Holy War between Hades and Athena. During this mission, Phantasos, Oneiros, and Ikelos head towards the outskirts of Hades' territory and on their way encounter El Cid, who was looking for an entrance to the Dream World to rescue the soul of his companion, Sisyphus. Upon seeing him, Phantasos grabs his arm and begins to praise him, provoking El Cid to attack them with his Excalibur. However, Ikelos intervenes and, using his abilities to distort space, returns the attack to El Cid, causing his arm to be amputated. Afterwards, Phantasos decides to keep El Cid's severed arm as a souvenir, and along with Oneiros and Ikelos, retreats, considering his opponent defeated. Phantasos goes to the place where Yato and Yuzuriha lie asleep due to the power of Hypnos's barrier. Upon arrival, he takes their souls to the Dream World, as the mission has concluded with the capture of Tenma of Pegasus by Oneiros. However, upon passing through the door leading to the Dream World, he suddenly notices a rip in space behind him. At that instant, El Cid appears and attacks him with his Excalibur, causing a wound to his face. Phantasos's anger and frustration cause the illusion that gave him the appearance of a girl to vanish, revealing his true appearance. Surprised, Phantasos asks him how he managed to enter the Dream World, to which El Cid replies that the fragment of the Cloth in his hand that Phantasos had taken summoned the rest of his armor, allowing him to enter this place. Then, El Cid splits Phantasos's body in two with his Excalibur.

Phantasos enjoys assuming the appearance and personality of a woman for unspecified reasons, although it likely stems from his personal preferences and his desire to hide his true face, possibly to disconcert or surprise his adversary. Some disturbing and perhaps unsettling characteristics can also be observed in him. For example, when Yuzuriha is unconscious, Phantasos approaches her and licks her cheek. Similarly, when his brother cuts off El Cid's arm, Phantasos takes the severed arm tenderly and keeps it in his collection; an action that would eventually cost him his life. Finally, like his brothers Morpheus, Ikelos, and Oneiros, Phantasos is guilty of arrogance, a quality typical of gods.

Phantasos's true appearance is shown very little in the story. Only when El Cid dispels his illusion is it revealed that he is an attractive and slender young man, with delicate features and feminine traits that give him the appearance of a "bishōnen" (pretty boy). He also has very long blonde hair, which frames his face when held up by the "mask" (helmet) of his Surplice. Most of the time, Phantasos presents himself under an illusion that gives him the appearance of a beautiful young woman, giving him a more prominent bust, wider hips, and reducing his height by 10 centimeters. Although in this form he still retains some features of his true appearance, such as the color of his hair and how it is styled, as well as some facial features. Furthermore, the Surplice he wears also changes, as it now appears to be adapted to a female body, with a smaller skirt and less leg protection, leaving his thighs exposed.