@Talh
Jesus rezzed that one dude and multiple religions sprung up to worship him, lasting thousands of years with hundreds of millions of followers. Imagine the kind of devotion gods'd get if they share their power and give their most devoted workshippers (priests) a permanent 99.9% mana reduction buff to boot. That is to say, Mr. priest will
never abandon his position.
@FgoSegul
There seems to be no penalty for just leaving the corpse there. Katalina was preserved with a bunches of ice blocks for example. However it looks like the longer he leave them, the more time and mana would be needed to counteract decomposition. So he'd rather just do it as soon as possible.