Pronounced: Emeal Cast Tag Near
Age: 16 years old
Height: 169 cm
Weight: 60 kg
An orphan from the destruction of Palmacosta when the Kharlan tree went out of control in the previous ToS. He is a boy of pure nature, making him believe in everything that he has. He can be, however, cowardly at times, giving him the inability and will to make his own decisions. He does, however, possess a strong heart. In order to protect Marta, he binds himself into an irreversible contract and becomes a "Knight of Ratatosk."
On a normal day, he hears a monster's cry from afar. Feeling as if the call was for him, he leaves his village and investigates. That is when he meets Marta. She tells him that someone is after her, and that's when they agree to join forces.
Later, he finds out that the cry he heard was from Tenebrae. He makes a contract with Tenebrae, making him into a Knight of Ratatosk. Whenever he uses Ratatosk's power during battle, his eyes turn red and his personality changes into something a complete opposite of who he really is. Some see him as a monster because of this.
Emil wields a sword in battle, like most of the traditional heroes.
He is portrayed as a coward, but promises to protect Marta Lualdi, the bearer of the Ratatosk Core by forming a contract with the lord of monsters, Ratatosk, thus making him the Knight of Ratatosk. He gets strength to fight against against monsters through this contract, making his voice deepen, his eyes turn red, and his attitude bolder. When in that form, Emil is more violent and blood-thirsty, which is why some call him a monster. This form is later on called Ratatosk Mode.
Emil is not really Emil Castagnier, but a fabricated personality created by Ratatosk. The name Emil belongs to a person who supposedly died during the Blood Purge, but because Ratatosk did not know how Emil looked like he assumed the shape of Aster. With the identity of Emil and physical form of Aster, Ratatosk was able to change his natural shape after being attacked by Richter Abend. Emil's memories and a false personality were imprinted into the new form, leading to the Emil who acts as the one you know and love.
The real Emil Castagnier's father and mother were named Reysol and Lana Castagnier respectly. They were probably against Lloyd, hinting this when they were afraid for Lloyd killing them in the Blood Purge. They are killed and with her last breath, Lana tells Emil (Ratatosk in Aster's form) to go to her younger sister in Luin, Flora, and her husband, Alba. She then dies.
By going here Emil meets Marta.