Gorion

Gorion was a skilled spellcaster, a learned sage and a respected Harper. He lived in the library-fortress of Candlekeep during the times when he wasn't adventuring. His perhaps most notable impact on history was his raising two Bhaalspawn children, one of whom especially played a crucial part in the fulfilling of Alaundo's prophecy of the Bhaalspawn (detailed in the Baldur's Gate series) as an adult, being the main protagonist of the stories. According to the novelizations of the videogames, this Bhaalspawn was Abdel Adrian. The other, who was also involved but played a lesser role, was Imoen.

Gorion raised the first Bhaalspawn in particular as his own child in Candlekeep. When he found out about Sarevok's plans to kill the protagonist, he fled from Candlekeep with them, leaving Imoen behind because she was not known to be a Bhaalspawn and thus was safe. It was too late, however, and they walked into an ambush. The protagonist survived the ensuing fight, but Gorion was killed.

Gorion's friends among the Harpers included Khalid and Jaheira, whom he instructed the protagonist to seek out in case they should become separated from him.

The novel
The history of the Gorion presented in the Baldur's Gate novelization was, unsurprisingly, slightly different from the one seen in the games. He raised Abdel Adrian as his son, but by the time of the story Adrian had left Candlekeep years ago, and Gorion had to send out for him so that they could flee together. The ambush in which Gorion died involved both of the two fighting several human mercenaries, Gorion using his staff only. Adrian defeated the mercenaries, but not before one of them had wounded Gorion fatally. Dying soon after, Gorion used his last strength to heal Adrian. He buried his body, but it was subsequently dug up and eaten by ghouls.

The games
In the games, Gorion was reportedly a powerful mage, though in one cut scene he also used a healing spell on his foster child (the protagonist). He raised the protagonist in Candlekeep for most of their life, right until he found out about Sarevok's plans. Not deeming Candlekeep a safe place to stay anymore – two highly incompetent would-be assassins had in fact already got inside with the intention of killing the protagonist – he gave with his foster child some gold and told them to prepare for the way. That night they set off without explanation, but while travelling along the Lion's Way they were ambushed by Sarevok, his lover Tamoko and a pair of ogres. Sarevok demanded Gorion hand over the protagonist to him but Gorion bade them to run and battled with the foursome, using his spells to kill the ogres and incapacitate Tamoko. Sarevok attacked him last and, largely unaffected by his magic, soon cut him down. He was later buried by the monks of Candlekeep.

Before settling down to raise the protagonist (and later Imoen), Gorion had been an active adventurer and Harper. Among other things, he had faced the dragon Firkraag and emerged at least somewhat victorious, enough so that he survived and Firkraag was left scarred. When he acquired the guardianship of the games' protagonist, he told almost no-one of their heritage; not even to themselves, or to close friends such as Khalid and Jaheira, the two of whom would be staying at the Friendly Arm Inn at the time he was killed and whom he shortly before instructed the protagonist should seek out if they should become separated from him. Ulraunt seemed to know, and he never approved of Gorion bringing such a ward to Candlekeep. Elminster, another acquaintace of Gorion's, also knew, and he was indeed the one who warned Gorion about Sarevok's plans in a letter. In the original Baldur's Gate, Gorion tells the protagonist in a letter (after his death) that they were the child of a woman who was Gorion's friend and one-time lover and who died in childbirth, but in Baldur's Gate II: The Throne of Bhaal the shade of Gorion reveals that the mother was really a priestess of Bhaal who had planned to sacrifice her child, a fate from which Gorion saved them.