Remus Lupin
Adventurer
Even by the strictest construction of responsibility, Belkar has already been responsible for the death of one of the creatures listed in his question, namely the oracle. So, I don't seen any interpretation by which the prediction has *not* been fulfilled.
But that's Belkar's prophecy. fba827 referred to Vaarsuvius' prophecy, which was that he would achieve complete and total ultimate arcane power "by saying the right four words to the right being at the right time for all the wrong reasons". Nothing in there about dying. Durkon is the one whose prophecy involved his own death.
If I remember Logic 101 properly, "or" is an exclusive construction. In other words "X or Y" implies "Not X and Y," thus, Belkar's killing the Oracle means that he cannot be responsible for the deaths of the others.