Prince Ariona Allant, the son of the Old King Allant, travels under the alias "Ostrava" to avoid drawing attention to himself. He wears a full set of Fluted Armor, and wields a Rune Sword and Rune Shield. He is encountered in body form four times as the player moves through Boletarian Palace, if he is rescued each time. After each of the first three encounters, he can be found sitting on the beam between the Boletarian Palace and Valley of Defilement archstones on the bottom floor of the Nexus.
Ostrava arrived at Boletarian Palace after the scourge, but shortly before the player. He has come alone from the distant Southern kingdom, likely one of Latria's territories on the edge of their kingdom, on a mission to find his father and confirm if the rumors that he has become a Demon are true. The prince is a wise, but pampered man and often becomes overwhelmed by even weak enemies and must be saved numerous times by the player. At first his motives remain hidden, but it soon becomes clear that Ostrava wishes for an audience with his father, King Allant. Throughout his quest, the player character encounters Ostrava in several unfavorable situations. Each time he is saved, Ostrava speaks more of his mission for the truth about his homeland of Boletaria. His search is an ill-fated one, and he soon finds that he's doubting himself when it becomes clear that Boletaria has dramatically changed since his return.
He speaks with authority on events which transpired shortly after the scourge, but since he was not present at the time, his knowledge is likely secondhand and may not be reliable. For instance, the Narrator describes in the prologue that Vallarfax broke through a gap in the Deep Fog to tell the outside world of Boletaria's plight. Ostrava states that Vallarfax was "lost" and that Biorr was the one to break through a fissure in the Deep Fog.
Ostrava speaks firsthand of what the Southern kingdom of Latria thinks about the Northern kingdom of Boletaria, and he is clad in the armor of a Latrian knight. He also possesses a telescope made by Latrian craftsmen and wields the sword and shield of a Latrian hero. This all indicates that Ostrava spent a great deal of time in Latria, possibly under the care of his relative, Lord Rydell, who is most likely uncle to Ostrava and thus the brother of King Allant. Biorr also speaks of Ostrava "coming to Boletaria," indicating he was not present at the Boletarian Palace when the Demon scourge arrived.
Ostrava is clad in the garb of a warrior and wields the weapons of a legendary hero, but he lacks the will to fight and will run when faced with a marginally powerful enemy. He is last encountered by the player on the steps to King Allant's throne room. Ostrava does not realize that knowledge comes at a price, and upon learning the truth that his beloved father is part of a demonic farce, Ostrava begins to unravel. He is overcome with grief and a sense of betrayal at his father's hands. Ostrava then kills himself at the foot of his father’s palace, offering his belongings to the player character and requests that you slay his father, King Allant, so that no more harm can be done to Boletaria. He leaves it to the player to finish his job and within minutes he appears in phantom form as the last obstacle to King Allant.