Apollo has red hair and a scar on his face. He wears green clothes and some feathers as necklace.
He acts like an animal and even goes to hunt to the forest. However, he also has a warm and caring side, this is shown when he keeps Silvia and Sirius secret of them being Shadow Angel hybrids. He even tries to cheer Silvia up by giving her a statue.
A feral youth from Arc City, he was found by Silvia and Pierre during their expedition to find the mythical "Solar Wing", whom they at first thought was him. His talents as an Element manifested when the Shadow Angels seized all of the citizens of the city. Due to his inherently animalistic nature, the ferocious nature of his abilities surged in a berserk fury unlike any of the Elements or DEAVA had seen, thus solidifying his status amidst their ranks.
Apollo gradually learns and acquires new talents, as well as showing his amazing ability to pilot Aquarion. Eventually, it is revealed he carries only a part of Apollonius' reincarnated soul. Following the collapse of the Tree of Life, Apollo bravely chooses to sacrifice himself, along with Sirius and Toma to restore the world. However, he promises Silvia that he will return in 12,000 years (although it is never explained precisely why this particular time is chosen, it could possibly be some reference to the next reincarnation cycle).
His name, uniquely, is not originally his own. After swimming in a frigid lake in the dead of winter, his childhood friend, Baron decided to name him Apollo after watching the sunlight bathe around his frame. This is a clear homage to the true Greek God Apollo, who was stated to have been born in the bank of a lake.
In the Aquarion: Wings of Betrayal, Apollo lives by himself in a forest where he and his grandfather once lived, and where he continues to live with the creatures of the forest 2 years after his grandfather's death. In his time in the forest, he has bonded with the creatures and trees and is able to understand them, causing him to want to protect them. Apollo often has to kill his friends as they were dying from wounds, in which he would grant them a quick painless death instead. He would keep their skulls as a memorial near his grandfather's grave. Apollo would claim that by eating the forest creatures and plants, he allows them to live on in him, giving thanks to them. Apollo lives in a cave which he has placed a bed and several textbooks, likely from his grandfather.
Apollo is first seen in a full cloak roaming in the forest, during DEAVA's clash against Toma. He witnesses the battle with the Assault Aquarion, which destroys the forest with its steps. The pain of the forest's destruction awakened his reincarnation and channeled his ability, alerting Reika (who believed herself to be Celiane's reincarnation) and Toma to his presence. He captured Silvia and Reika as they crashed-landed in his forest. For causing destruction to his home, he locked them up in a small, makeshift jail in his cave-like home. He shows kindness to them even though they destroyed part of his home by giving them food and explaining his views on the forest and its creatures. Being a makeshift jail cell, Slivia and Reika were able to break free due do Silvia's element ability. In the meantime Apollo is visited by Gen Fudou in a dream who urges him to look beyond the world he sees (in a mock fight mimicking the opening theme's animation from the original anime).
When Silvia and Reika left to go outside, they saw Apollo swimming and bathing. Apollo openly approaches the pair, naked, (after a flock of flying birds apparently informed him of their escape) and shows them his grandfather's grave. He further discusses his beliefs with Silvia while Reika noticed the forest was the ruins of the ancient city Apollonius and the humans used as a base in the war against the Shadow Angels. At this point, Toma appears in an image and attempts to lure Apollo back. when Apollo claims his passion for the forest, Toma start to to burn it with his singing. The destruction enraged Apollo which awakened the legendary Aquarion vectors. He merges into Aquarion Sol with Reika and Silvia (who he called out to as Scorpius and Celiane). The OVA ends with Aquarion's Infinity Punch chasing and eventually hitting Toma's Cherubim Soldier.
In Aquarion: Wings of Glory, it is revealed that Toma was disappointed with the unawakend Solar Wing's power (as Apollonius' punch would reach to the moon). He proceeded to overpower Aquarion which lead to Silvia's hospitalization. While Apollo would visit Silvia and adjust to the new DEAVA base, Reika and Silvia would have their memories of past lives manipulated by Toma's feather, eventually leading to Apollo being stabbed and Silvia becoming the prime suspect.
Gen confronts Apollo in his healing process and delivers a Gen-style typical lecture, to which the both laugh at his not following. As Silvia attempts to escape in Vector Luna, Apollo gives chase in Vector Sol. Silvia expresses her worry that she is Scorpius' reincarnation (even revealing her Shadow Angel wing) and that she may try to kill Apollo again, which Apollo responds to by forcing a merge with her. Reika, Jun and Tsugumi follow in the Assault Vectors and merge to confront the pair.
When Reika's emotions cause the formation of the Beat Aquarion, Pierre arrives in Vector Mars and merges to form Solar Aquarion, awakening the memories of the reincarnations from 12,000 years ago, showing the destruction of Atlandia and Apollonius's death. At their breaking points, Toma and Otoha arrive in Cherubim Soldiers and reveals the feather he implanted in Reika as well as the truth of her being the person who attacked Apollo. He also reveals that Reika is the real reincarnation of Scorpius. This breaks the merge in the Assault Aquarion and allows Pierre to switch places with Reika (and free her from the feather).
Otoha confronts Pierre and the Assault Aquarion whilst Toma fights Apollo and the Legendary Aquarion. Pierre's team seemingly wins against Otoha and returns to aid Apollo against Toma. Tomas' Barrier appears unbreakable at first but Pierre uses the Shadow Angel's feather he took from Reika to augment his own power (Like Glen had in the anime). The power increase almost defeats Toma, but a surviving Otoha sacrifices herself to blow up the Assault Vectors, causing the awakening of Aquarion's Solar Wings.
A following battle acts as Toma's plan of commencing the Ceremony of Wings, which crystallizes the world in Ragnarok and impregnates Toma's Cherubim. However, Apollo and Silvia's love causes Aquarion's power to overflow causing the immediate miscarriage of Toma's child. Enraged, Toma severs Silvia's arm and forces Aquarion to split.
Apollo, in a dream like state, calls to Silvia and Reika, who appears to be resenting the destruction they have caused. They then come to understand that the reason Aquarion is in three parts is to prevent to strong a love between two of the pilots, which would cause the destruction of the world. They then preform an Infinity Punch to defeat Toma once and for all, which they follow up with the ultimate Genesis Infinity Punch that revives the world anew. The OVA ends stating that the Genesis punch affected the time space continuum in such a way that it affected another world, (which is shown to be the world that the anime takes place in) causing the Apollo of that world to briefly see Silvia's feather (and Silvia and Pierre remembering his name as they hunt for Solar Wing).
Apollo's primary Element powers focus on his animalistic sense of smell, agility, and climbing abilities. He can fight like an animal and is very flexible. Other than that, he is also the only one show to be able to use Infinity Punch in Solar Aquarion. He is also the holder of Solar Wing, granting him the ability of producing phantom wings, flight, and the awakening of Aquarion, which causes him to hear Apollonius' voice.
Baron was Apollo's best friend when they lived together in Arc City with their friends Chibiko, Hanatare, Megane, and Maji (otherwise know as the orphans that Baron and Apollo cared for). It is shown that when Apollo was a young boy, he and Baron lived in the same internment camp. Apollo was shivering outside in the fallen snow when Baron shared half of his loaf of bread with him in the winter when they were both starving. He also gave Apollo his name when Apollo swam in a lake on a winter morning, saying that he got his name from "the mythical god of the sun". The two were essentially brothers to each other, and Apollo's original reason for piloting Aquarion was to save Baron and the orphans from the Shadow Angels after being Harvested. Baron dies in later episodes do to one of Toma's ploys, and tells Apollo to "take care of the little ones" in his place.
Silvia de Alisia
Pollon, a Shadow Angel with the appearance of a winged hound, fell in love with Celiane and wished that "If [he] was reborn, to let [him] meet Celiane again". His dream came true and Pollon was reincarnated as Apollo. Fate then brought the two together. They started to fall in love with each other. At the end of Genesis of Aquarion, Apollo entered the Legendary Aquarion along with Toma and Sirius, leaving Silvia behind. Before he left, he kissed her and told her that they would meet again after 12,000 years. Now, in Aquarion EVOL, Kagura, Amata and Mikono (who are the reincarnations of Silvia and Apollo) meet again.
Sirius de Alisia
Sirius is presumably the other half of Celiane's reincarnation. When he was interacting with Apollo, he felt rivalry towards him. He battled with him for the title of the Solar Wing, claiming that he was Apollonius true reincarnation.
In the series Genesis of Aquarion, Apollo and Reika had a friends relationship. However, in the OVA, Reika started showing affection for Apollo, claiming that she was the reincarnation of Celiane and that he was the reincarnation of Apollonius and that they were meant to be together. However, at the end it was revealed that she was the reincarnation of Scorpius, who attempted to kill Apollonius. Despite this, Apollo, Silva and Reika united to defeat Toma.
Gen Fudo was like Apollo's mentor. He taught him things about the Aquarion and gave him special lessons. He saw Apollo as the new pilot of the Aquarion.
In Genesis of Aquarion and it's OVA, Toma thought that Apollo was the reincarnation of Apollonius and thus lusted after awakening him. He would set up a series of challenges to both collect Prana for the Shadow Angels as well as progressively awaken Apollo, though acting in very twisted and teasing ways to do so. Once awakened, he attempted to force Apollo to join him in his various goals (in the original anime fertilizing the Tree of Life, in the OVA creating Ragnarok and impregnating himself), failing in both. In the original series, after failing to fertilize the Tree of Life, Toma merges with Apollo in Aquarion to aid in replacing the Tree of Life, happy to finally be one with "Apollonius". However, after Toma found out that Apollo was never the reincarnation of Apollonius, he fell into despair and anger and became the persona known as Mykage in Aquarion EVOL. In Aquarion EVOL, he was the one responsible for separating Amata's soul, whom is the reincarnation of Apollo, into two.
He is the reincarnation of Pollon, Apollonius' dog. This was originally intended to be revealed in the first series, and hints were dropped to lead up to it, but it was sidetracked by the romance subplot between Apollo and Silvia. Nonetheless, he was explicitly stated to not be the reincarnation of Apollonius, leaving his past life a mystery until it was revealed in Aquarion EVOL.
Apollo and Silvia shared their first kiss in episode 3, Element school, by accident while in the vector simulators.