Cornelius was the fourth King of Altea, it is said King Mostyn, the first king of Talys was a close friend of his. When the War of Shadows began, Cornelius took his knights to fight on Archanea's behalf.
Cornelius tried to fight against the invading forces of Dolhr and Grust's Sable Order of Knights with Anri's sword, Falchion. but he was betrayed by his ally, King Jiol and killed in battle. Only one of his knights, Cain, survived, escaping to tell Marth about his father's fate and last words telling his son that it was now up to him to save Archanea.
It is never specified which individual killed Cornelius in the games. In the anime, Cornelius is killed by Gharnef's Imhullu spell, so this may apply to the game continuity. This seems probable because Gharnef is in possession of the Falchion. However, the opening of chapter 14 says King Jiol of Gra was the man who robbed Marth of his father, and Malledus indicates the Falchion resided in Gra before being taken by Gharnef. Camus says to Marth that he played a part in his father's murder.
While Cornelius never appeared within the game, he was described as a powerful swordsman and general in his own right, known for being a Warrior King. Loyal to Archanea kingdom, Cornelius was always willing to fight on it's behalf. It is said by the narrator for Fall of Palace that he put up a worthy fight against Camus's Sable order. Cornelius was described by his son as a noble ruler.
Fire Emblem OVAEdit
In the Fire Emblem OVA, Cornelius' character is slightly expanded on. He is shown to be severely strict of Marth's training so he can live up to being Anri's descendant. He disapproves of Marth's gentle nature, and even hits him across the face for not taking the life of a deer during hunting. Cornelius's death at the hands of Gharnef is shown, with him sending Jagen away to protect Marth. This is different in Shadow Dragon, where it is Cain who was sent to save Marth, with Jagen having already been at the castle.
In the manga, Cornelius suffers the same fate as he did in the game. When Marth visits Port Warren, he is attacked by a child with black magic, which imprisons him in a dream he cannot be woken from. He dreams of Altea and encounters both his parents, who begin to preach that humanity is inherently evil and that they can only be saved by Medeus. Marth realizes this is not how he truly remembers his mother and father, and he tells them to leave his memories of them alone. They then disappear after it is revealed as an illusion designed by Gharnef. Marth escapes the nightmare with Merric and Gotoh's help.
Cornelius is a masculine Roman name, possibly derived from Latin cornu "horn". The gens Cornelia was one of the most distinguished and important families of Ancient Rome, which may reflect Cornelius's royal status.