Sylia tells the battle versus aliens trying to absorb the planet's energy.
The game has the particularity to feature talking animals as main heroes.
Katie is the original hero's cat, and Nestor is the heroine's dog. Both take over the mission to save the world when their masters fail at it.
They meet other animals along their way and convince them to join and try to ruin the aliens' schemes.
A skilled warrior, good with both physical and magical abilites. Simon is the leader of the famous Sylian party which role is to enter the main Alien's cube and defeat their queen.
A calm and kind woman, master of healing spells, she's always ready to aid her friends and always support Simon's decisions.
A powerful wizardress and also a member of the Sylian party, Alison handle powerful spells and some spells to support party members.
Always ready to cut something with his Axe, Boris is a fearless knight and is the fourth member of the Sylian party. He doesn't have any spell but his physical attacks can do great damages.
The main character of the game, Katie is Simon's cat and a corageous little animal. After the defeat of the humans, Katie along side with Nestor, decides to go on a journey and try to stop the evil schemes of Lady Godiva, the Alien's queen.
Nestor's is Nancy's cute dog. A bit coward sometimes but a loyal companion, Nestor is Katie's best friend and is the first to help Katie in the dangerous mission to defeat Lady Godiva.
Hans is a rooster that lives in Saffron. Dumb and noisy, he sometimes ends up screwing the party's strategy. But he can trick his enemies with some noisy shouts.
James is a very lazy sheep. He is found in a small grass spot south of Burroughs. James is not very fond of fights, however he agree to help Katie and Nestor, he's just happy to be able to follow someone.
Evelyn is a kind and generous cow. She can help her companions by giving them a little of her mlik. She also has a powerful attack power.
Known as the Aselian beauty. Rosalyn is a beautiful horse and always brag of her beauty, which sometimes bothers the other party members, and thinks that there's no one prettier than her.
First seen in Mt. Horus, Eli was first looking for allies to defeat the aliens, when he meets with Katie and friends and joins her to fight against the aliens.
A tiny little butterfly, Demi used to live in Turtle Cave before the aliens transforms the place into one of their strongholds. She was about to leave her place, until Katie and friends appeared and decided to help Katie in the mission of getting rid of the aliens.
Eli's brother, Roth is an optional character that can be found in the top of Mt. Horus after activating his quest. Roth is a cold blooded, lone wolf that doesn't care for what's happening around the world, but Eli convinces him to join the animals band and defeat the Alien Queen.
Sylia is the second game co-produced by Aldorlea after Ella's Hope.
Sylia was originally called Katie's Quest.
Sylia is the second Aldorlea Game that players can name the characters, after Asguaard.