Magadon Kest

Magadon Kest is a close friend of Erevis Cale and Drasek Riven. Magadon appears to be a hunter, but his milky white eyes betrays that there is more to this man. Under his hat he hides two horns, a telltale sign of his fiendish heritage. Born to a human mother, Magadon was sired by none other than the Archduke of Cania, the ruler of the eighth layer of Hell, Mephistopheles.

Background
Magadon's status as a "mind mage" (psionicist) plays an intricate role in his time adventuring along side Cale, Jak, and Riven This is most prominent with the raising of the ruined Netherese floating city of Sakkors. Magadon's interaction with the quasi-sentient mythallar, simple known as the Source, is a pivotal, though not well known relationship that had grave consequences for not himself but Faerun as a whole. In fact, he was captured by the Shadovar so that they could use him to awaken the Source. Rivalen Tanthul forced Mags to give in to the Source and in so doing, trapped Magadon in his own mind until Erevis and Riven freed him from Sakkors, but unfortunately this did not keep him completely from harm. As he transported Cale and Riven from Sakkors, he accidentally sent them to Cania in which Mephistopheles threatened to kill all three. Cale struck a bargain with the arch-devil so that his friend would be spared, but at the cost of handing over a piece of Mask's divine essence and betraying Mask himself. To ensure Cale lived up to his promise, Mephistopheles split Magadon's soul in half, keeping Magadon's human side as collateral. Magadon from that point forward tries to overcome the demon inside. He even puts both his friends at risk on a few occasions due to the unpredictable state he is in.

In the end, Magadon succumbed to his demonic nature and tricked one of Erevis's followers to lead him to the Source. He let the mythallar consume him and in the battle between Saerbian refugees and Kesson Rel's forces he nearly wiped out both ally and enemy alike. At that point, Cale traveled back to Cania to deliver Mephistopheles his prize so that Mags didn't kill the refugees. In order to give the arch-devil the divine essence Cale needed to sacrifice himself.

Magadon's ultimate fate leads him to a life of mediocrity, operating a small tavern, called The Tenth Hell, in post-Spellplague Selgaunt. He still to this day is humbled by Cale's sacrifice and when Riven informed Mags of Cale's son, he helped search for him also.

Recent Activity
Magadon ended up fleeing Selgaunt with a group of adventurers working for Riven. Shortly after that, he was sent to Neverwinter along with a shade by the name of Vincent, who also serves Riven. They were to investigate Shadovar activity in the region and report their findings.

References:

Forgotten Realms Wikia

The Erevis Cale Trilogy by Paul S. Kemp

The Twilight War by Paul S. Kemp