Just who was Balthazar? *Spoilers*

[Dolyngwen]

So I know here was Ketheric's advisor but I read some notes on him in the game and it seems his ultimate goal was to betray everyone to his god. He also says that he took the name Balthazar from someone who was killed, perhaps by him?

He's some sort of undead necro but can't seem to figure out just where he came from....

[jait]

He's another Chosen but not Chosen of Myrkul. It's suggested he's the one who rezzed Isobel and soul caged the Deva but not Deva for Ketheric's immortality. If it's not in Act 1, it wasn't finished or polished. Clearly there was meant to be a much bigger story surrounding the Thorm family and Balthazar but alas...

[Taifun_Vash]

Technical, he said he took the name Balthazar, together with the ribcage of the original owner.
I just interpret it as his admission to killing the original owner.

[Hopper]

The original Balthazar was a douchey Bhaalspawn from BG2: Throne of Bhaal. The player killed him over a hundred years ago in a tiny village in Calimshan.

The new Balthazar guy just stole his identity and ribs, for some reason. None of it makes any sense, especially when you realise that all bhaalspawns turn to ash when they die....