Karzahni was confirmed dead by the toa Nuva after finding his body, but he was killed by a simple stab wound, from a Matoran? I know that his mind was scrambled by makuta teri, but it was indicated that he got it back. Just seems a bit suspicious, more like he made velika and the other toa believe he was dead to accomplish another goal.
“I consider him to be dead”
Official Greg Dialogue, July 26, 2010
“Karzahni died on Spherus Magna”
Chat with Greg Farshtey, November 1, 2013