Arawn (GoDs)

"Arawn is the God of the Underworld that is guarded by the The Cailleach, he has many soldiers but the most terrifying were the Dorocha, he was once a Druid whom Drank from the Font of Power and Bathed in the Pool of Knowledge. By binding himself to Magic, by becoming a God, he caught the eye of the Goddess of the Underworld and became her consort."

- Gaius reading from a book about Arawn, reading parts of his history.

Arawn is the Ancient Celtic God of the Dead and the King of the Underworld, known in Norse mythology as Nidhogg or Loki, in Roman as Pluto and in Greek as Hades. He is a major Anti-Hero and Antagonist in the God of Death series.

Arawn was sealed away less than one hundred and fifty years before the beginning of the Merlin series and every fifty years he would project from the Underworld his spirit to possess a new body he had recently created, by being physically sealed away into a dormant state where whilst his mind sleeps his spirit is free to roam the Underworld.

This fifty years his Vessel was actually to be Merlin, whom he made sure to incubate magically in the womb of Hunith in preparation for that time, but it became unnecessary when Arawn was awakened by Mordred.

Life as a Druid
Legends say that Arawn was born to be the strongest Druid of his time, a Prodigy of Magic both light and dark, he sought to be the greatest warrior and Sorcerer of the time when the Old Religion was still the strongest Government that ruled in Albion that worshiped the Underworld and its King: Hafgan. Both King Hafgan, and an unnamed Rival Queen were in constant conflict, both trying to reign over the dead.

Arawn eventually crossed over into the Underworld in a similar sacrifice to that of Lancelot however he had a goal in mind, in the Underworld he found a means in which to travel to a Higher Domain: the Domain of Gods, there he drank of the Font of Power and bathed in the Pool of Knowledge

Trivia

 * In Welsh mythology, Arawn was the king of the otherworld realm of Annwn, appearing prominently in the first branch, and alluded to in the fourth.
 * Arawn does not mention having a Wife in Merlin, but he does admit that his sister lives with him, showing differences to the original mythology. It is mentioned that he married the Queen of the Dead, whom he allowed to be killed and absorbed by King Hafgan, so that he didn't have to kill her himself when instead Killing and absorbing Hafgan took out two birds with one stone.
 * Arawn's actor is actually the American Actor Kevin Zegers, it gives Arawn a sense of abnormality having an american accent and introduces a unique element to the Arthurian Mythology, an element that ties into the fact that Arawn has been sealed away for exactly 150 years.
 * Arawn has similarities to Hades from the Saint Seiya franchise, despite being powerful both physically and supernaturally, both Arawn and Hades wield a Soul Sword.