Astyanax is a sixteen year old kid with a muscular physique. He has red eyes and blonde hair. During his time on Earth he wore a blue and white T-shirt. When transported to Remlia, he is given blue armor to help protect him.
He is a student from Greenview High School who always has recurring dreams of a woman calling his name. One day, he is transported to the land of Remlia by a fairy named Cutie who tells him that the woman is Princess Rosebud who was kidnapped by the evil wizard Blackhorn, who plans to drain the princess of her magic to become even more powerful. Cutie gives him the magical axe Bash which can transform into a spear and a sword. Cutie then tells Astyanax only the Princess's magic can send him home so he sets out to defeat Blackhorn.
Blackhorn learns of Astyanax and sends his monsters after the boy. Astyanax is able to defeat Blackhorn's minions and eventually reaches Thelenia, Blackhorn's castle and faces Thorndog, Blackhorn's most powerful servant. Despite defeating him, Thorndog places a death curse upon Astyanax so the boy would die with him. To save him, Cutie sacrifices herself to erase Thorndog's seal, despite Astyanax's protests.
Astyanax is freed from the curse and honors Cutie's sacrifice by facing Blackhorn in battle. He easily defeats Blackhorn but Blackhorn reveals his true form as a dragon. Despite the difficulty, Astyanax is able to kill Blackhorn and saves Princess Rosebud. Rosebud offers to throw him a party as thanks but Astyanax asks to be taken back home on Earth.
He returns home, but during his walk home, he walks upon a young girl who looks like Cutie. The girl hugs Astyanax and reveals Rosebud revived her as a human so she could be with him. Astyanax look up at the setting sun and sees an image of Rosebud saying the two being together was their reward for saving her kingdom.
There is an arcade port of the game but the character's name is Roche and the story is completely different.
Astyanax's name comes from Greek Mythology.