The formerly deceased Mentor of Ryoku/Kohr. As a wyvern, Aion has an unusual amount of magic powers, and even knows some rare magic spells (especially from the Carnage/Blood Element). Born the prodigy of the Serket tribe, Aion can be somewhat of a prideful person, especially when he was under the influence of the Carnelian Core's soul. As he was previously deceased, Aion will sometimes have flashbacks into his previous life, and will experience phantom pains from his death. Because he had been blinded while protecting Ryoku as a teen, Aion has somewhat raised senses of hearing, touch, smell and taste. His sense of sight, while decent, isn't always the most accurate when it comes to aiming. In general, through life experiences, Aion fights much better blind than he does visually. This may be due to instincts/habits, and the fact that he has the ability to use Aura Vision.
Though he's able to use a bow and arrows, and his bite and horns can be incredibly painful. Aion does not prefer to fight physically. In possession of Mind Magic that's heavily boosted by his Blood Magic skills, Aion can lift people with ease using telekinesis. If especially enraged, he'll take to tossing his victims around like chewtoys, and displays something of a sadistic tendency. As he is Akibi's ancestor (and Akibi is his reincarnation), some traits Aion displays are shared (but hidden away) by Akibi as well. When Aion decides to use some Flame and Blood Magic together, he's able to form serious piercing attacks, often in the shape of arrows or needle-like feathers. As well, Aion can attack with sharpened feathers, although it's an attack that can be difficult to set up.
Aion has the ability to see the future due to his Mental Magic mastery. However, they come in randomly, and can even change if the situation is made well-known. This is why Aion protected Ryoku's baby form as much as he could, knowing his own death was pending (and thus protecting Kohr from going with him).
Though Aion was very coddling of Ryoku in his first life, in his resurrected state, he seems to be wary of Ryoku's loving presence. Perhaps he can sense that he's crossing boundaries... He also seems to miss his Partner, Aguka of the Four Souls, although he won't make any complaints in his new life just yet...
In regards to treating Takuto, Aion has seen a vision of the future upon reawakening as a spirit. Although he can't remember what he saw, the feeling of dread remains, and he treats Takuto somewhat callously upon first awakening as a result.
Because he junctioned his spirit onto a stone that was not his own, Aion occasionally displays unusual vigor and cruel tendencies, which is against his timid nature. His eyes have also gained partial heterochromia due to absorbing the stone's original soul. The repercussive effects of this possession is not yet known...
Aion was only a dragon-child when he died at 329. In his second life, he retains his teenager-like body, although one could say he's at least 1146 now...
Now in his reborn state, Aion has lost any influence the Carnelian Soul could've had on him, and lost the heterochromia he had as a result. In this life, he has seen many changes to the future. Satisfied with it, he eventually became Mates with Aguka, and occasionally visits Ryoku and Akibi's family, just to see how they're doing. Despite losing the Carnelian Soul, Aion retains a bit of the outspoken attitude influenced onto him.
After returning to the way he originally was with the passing of the Ragnarok's Cry, Aion lived with Aguka and the Four (later Six) Souls. When Zhoushen fell under a revolt by a vocal minority of extremists and radical demons, Aion offered up his life to restore that of Takuto's, also choosing to repair the Soul Bond that had become fragmented between Crysta and Takuto. Making the fix permanent (meaning Takuto will be able to "fragment" without losing the true Soul Bond's power) and giving Crysta and Aguka a few eggs and children before his death, Aion's last gift was a Seed to Crysta that seems to contain an integral part of his soul. While it won't be a true reincarnation, Aion leaves it with Crysta in the hopes that one day, his reincarnation will be able to comfort Aguka, who was left heartbroken after the sacrifice.
It is unclear if Aion's three wishes have come true. As a result, it's possible he'll never reincarnate or regain his memories if he does. He left with the hopes that the last wish comes true so that he may return to Aguka one day.
(I haven't drawn Aion in a long time, so sorry for the older references.)
A very old reference of Aion with a baby Ryoku/Kohr.
A more recent WIP of Aion (full body ref).