Demigods

Demigods are the children of gods with a being of another species.

Season 5
In Hammer of the Gods, the god Odin mentions that he will be killed by his grandson, the demigod Fenrir during Ragnarok.

Season 8
In Remember the Titans, Sam and Dean encounter a demigod named Oliver, who is the son of of the proto-god Prometheus. He had the same curse has his father, which was to die every day only to be brought back, a curse put on by Zeus. The curse was lifted by the death of Zeus.

Season 9
In Sharp Teeth, a cult of werewolves known as the The Maw of Fenris worshiped the Fenrir under the title Fenris. They that believed he would bring about werewolf domination of the world when Ragnarok occurred.

Season 13
In Unfinished Business three norse demigods, Sleipnir, Narfi and Fenrir, hunt down the archangel Gabriel for the death of their grandfather Odin after he escaped his captor, a powerful demon named Asmodeus. All three were killed by Gabriel in the process of trying to capture him by special swords that the angel made specifically to kill them.

Known Demigods

 * Fenrir
 * Narfi
 * Oliver
 * Sleipnir

Appearances

 * Season 5
 * Hammer of the Gods
 * Season 8
 * Remember the Titans 
 * Season 9
 * Sharp Teeth
 * Season 13
 * Unfinished Business 

Trivia

 * Fenrir has the most lore about him of all four on-screen demigods.