Killing Kenny in front of the cultists while he translated their legacies for them had been a bold move on Uriel's side to say the least. Kenny was a couple steps away from the strongest members of the society and thousands with thousands of cultists looking directly at him while they chanted their unnerving song. But it was necessary.
Atsa couldn't watch idly by as Kenny misinterpreted the ancient mysteries kept a secret for generations while Uriel couldn't stand Kenny soiling such valuable remains with a common marker. He didn't know nor did he care how did Kenny gain the ability to understand those ancient texts or even if he read them correctly, but using a marker on them was akin to destroying their cultural value. A sin he wasn't willing to forgive.