What if Xera already knew that someone might tamper with the aspects of Lazarus, and replaced all artifacts with fake ones? There were suspicions among the white mantle that not all were loyal to the cause, so the summoning of Lazarus would have been dangerous in the presence of defectors without some kind of precaution set in place- especially with the summoning of Lazarus being a public announcement among the white mantle. This strategy was employed in similar fashion with the ending of Death Note: createkittene notebook, display it in use for all to see, convince the spies that fake notebook is real, have spies replace pages of the notebook to make spies think they’ve sabotaged the notebook, arrest owner by catching him red handed using the fake notebook without any danger of death.