|Game||Tales of Symphonia:|
|Race||Human / Spirit|
|Occupation||Knight of Ratatosk|
|Character Designer||Daigo Okumura|
|JP Voice Actor(s)||Hiro Shimono|
|EN Voice Actor(s)||Johnny Yong Bosch|
Emil Castagnier (エミル・キャスタニエ Emiru Kyasutanie?) is a main character and the lead protagonist in Tales of Symphonia: Knight of Ratatosk. He is a timid person who is constantly apologises. He lost his parents during the Blood Purge to which Lloyd Irving is claimed to be held responsible for. He lives with his uncle and aunt, both who despise him. When Richter Abend attempts to kill Marta Lualdi, a girl Emil meets, he forms a pact with Tenebrae to become a Knight of Ratatosk, which grants him Ratatosk's powers; Ratatosk is the Summon Spirit of the previous World Tree and lord of all monsters.
During battle, Ratatosk's personality takes over giving Emil red eyes and an aggressive personality. As he journeys with Marta to gather the Centurion's cores to awaken Ratatosk, Emil discovers he is Ratatosk and that the timid Emil's personality and memories are a fabrication. He learns that the real Emil Castagnier died in the blood purge and that his physical appearance is an imitation of Aster, Richter's close friend. When Aster and Richter pleaded with Ratatosk to restore the worlds climate, Ratatosk killed Aster. Realizing Ratatosk bears a hatred towards humanity for the death of the past World Tree, Emil is unable to trust him and seals away his personality by using Verius, the Summon Spirit of Heart.
When the party confronts Richter to prevent him from opening the door to Niflheim, the world of demons, two outcomes are decided by the player. After Richter's defeat, Emil will either kill himself and have Ratatosk's core act as a seal to Niflheim, or persuade Ratatosk to resume guarding the door. In the latter choice, Ratatosk divides himself into two allowing Emil to live his life.