BTW it would have made a nice addition to the final Sarevok encounter in BG1, if he'd come out with the truth about your mother.
it implies that Sarevok is intimately familiar with both Gorion and Aliana's relationship development that you try to make extremely complicated and introduces a soap-opera feel to the ending of the game...
Just imagine:
(The doors of the Temple in AR0123 open and you see Z MOVIE)
Sarevok: Here stand I your brother and I am going to kill you once and for all, since you screw me up on numerous occasions lately, pup!
(short and to the point)
Wait! I forgot!
Let me put you through the moral torture first!
Remeber that Gorion's letter you got? Well, Gorion in truth was a delusional old man, who bored your mother to death with his goodness and his grey hair. So she decided to try the evil magic and went astray... Unlike all other women, she actually gladly went into Bhaal's avatar's bed and begotten you, my ill-conceived half-<PRO_BROTHERSISTER>.
But that's not the end of the story...
Gorion was chasing her, trying to convert her back every time he caught up with her. But she would not relent.
So when he learnt that she was pregnant, the old man lost the rest of his wits and imagined that the child she is carrying is actually his and should not be raised as EVIL.
Now, sit down, <CHARNAME>
THE REVELATION is coming.
It was GORION who killed your mother!
Yes, in his half-fanatical, half-mad state he had killed your mother and snatched you away.
*Sighs*
And, yeah, forgot to mention.
I am Alianne's son, just like you. That's how I know it all.
PC:
1. (falling in Sarevok's hands, weeping)
2. O, the Hells! The NINE FLAMING HELLS! Let us fight already!
3. Why do I have a distinctve feeling that the genre request one more revelation?!
4) Are you done with your villan's exposition bit, Sir?
Sarevok (repy to 1, random 50%): YES! My EVIL plan had worked! (kills <CHARNAME>)/game lost
Sarevok (reply to 1, random 50%): (the big spikey man weeps in your arms) the game tries to finish itself off, but has no idea how to without the final battle... CTD results
Sarevok (reply to 2): Yes, yes, I am getting to that! (game proceedes as normal)
Sarevok (reply to 3): *Yawns* Indeed (yawns) Remember Imoen? She's our sister too... (the game freezes, and you can almost see the expression of confusion on the avatars)
Sarevok (reply to 4): Pretty much. Shall we? (game proceedes as normal)