Jon Irenicus from Baldur's Gate 2.
A former elf (got stripped of his elven soul and was made a human), now human mage. The crime that got him exiled was a plot to gain divinity at the cost of an elven nation. Everything that comes after, is caused by Irenicus not having his soul, missing his former life, and wanting to regain it.
The only way to do this (at least as far as he is convinced) is to steal a divine soul. Hence you as the son/daughter of the dead got Bhaal get captured and experimented upon (which quite rightfully is mistaken for torture).
But the entire thing started from Irenicus's sister, Bodhi. She was the ambituos one. She was the power-hungry. She was also the cunning one and Jon Irenicus loved her dearly as a sister. What she asked for, Jon tried to get. Contrary to Jon, who was considered a mage prodigy. He was loved by the queen. He was held up as an example to other elves. He, literally, had it all.
All this spiralling down, while partly Irenicuse's fault, is mostly blamable to his sister. And the thing is, Jon might have very well accepted his punishment and tried to regain the favour of the elven gods and the queen (whom he loved as ruler and apparently as a lover as much as he loved his sister as a sibling) trough good deeds, but it was Bodhi who was supremely pissed off her plot to gain divinity via her brother was foiled and that they were made human. She was also the one to turn to the undead (making herself a vampire) to escape the curse and failed at that. The power of the curse put upon them by the Seldarine was more terrible to one who was no longer even human, making it absolutely necessary instead of merely highly convenient for Bodhi to regain a soul in quick order. Again, she manipulated her arcanely oriented brother into starting forbidden and immoral experimentation and research. And again led him down the path to hell by a noose for her own selfish desires.
Irenicus got supremely damned in the end by his actions, but he really just loved her sister who was the real, true evil intent behind it all. And in the end, when you witness him and the elven queen Ellesime talking, you see how bitter and desperate he had become. 'Irenicus' means 'Shattered One' and the name fits him well. Beautifully, beautifully executed ending to the last unexplained links in the story.
