The voice had been a particularly unusual foe, and yet it was not the worst of them. As Lex continued to lead the groups, they faced more and more enemies, each one either stranger or stronger than the previous one.
For a month, such a journey continued, and it came to the point where even Lex's confidence began to waver. He began to seriously doubt their ability to complete the quest - until he realized that he was facing against the living personification of doubt, and killed that too.
That didn't change the fact that their progress had slowed down significantly. Finally, Lex was forced to kill Jeziah because keeping such a prisoner with them was too much of a liability. It was a pity that Lex couldn't read his locked memories, but a pity is all it was.