Halcyon is a man with blue eyes and pale blue hair. He wears customized Lagiacrus Blademaster set consists of typical Lagiacrus Blademaster armor pierces without the helmet, a blue cape with maroon red underneath and royal golden stripe at the edge with numerous puff lining the lower edge, and underneath the waist armor is a silvery long skirt made from scale-like pieces and at the front is a blue fabric with a pattern of a swimming golden Lagiacrus holding four-leaf branch in its mouth, on his right ear is a small golden ring. His Kinship Stone is on his left glove.

The son of the chief of City of Water, El Te Una, Gaios. He is currently the acting cheif due to his father become sick.

Halcyon is a descendant of the Ten Dragon Knights, and has undergone various educations and trainings to be a rider as the next leader of house Una, who ruled the city for generations.

Although he comes from a well-known family, he is a friendly person, making him beloved by his retainers and people.

He also tremendously trusts his confidant, Ariyon.

To reveal the true identities of Black Riders who attacked his city, he decided to accompany the player in their missions.

Prior to become sick, his father Gaios collected all sort of weapons from all over the world in case Halcyon would eventually become the chief. This dragon element lance is one of them, as he brought it along as he received permission from the vault and become more active member of the Correspondent Observation Team.

Halcyon accepts his father's feeling in this weapon and vow to devote himself further.