My favorite character of all time remains Eric Azurain, who came into being because of a suggestion my DM made to me. He began his existence on the harsh world of Athas, in the Darksun setting; then from there, died and joined the ranks of those in the Seven Heavens. Oddly enough, along the way he fell in love with a tanari succubus, who also managed to fall for him.
Along the way, he ended up in a fight where his underlings of the angelic host and her demonic servants clashed - with him and her fighting back-to-back against the other side. She died from a spear blow; he went mad and forever stained his angelic inheritance by slaughtering not only the emaining fiends, bu his own angelic servants as well.
Some years later, still carrying her dead, waxlike body with him, he encounteed a god of total balance - who fused him and her, mixing their nature to create Eric Azurain as he is now, a human of total neutrality, inhumanly beautiful but with the personality of a rock. His mission in existence: to balance out good and evil, law and chaos, to preserve the world. He also has a fear of heihts, as a dim memory of his past.