Ah yes true, ideally it would also need to point out what classes it affects.

Enemies would be good. I went with Humans to make it clear that it doesn't affect buildings or siege.

"An Offering of Flesh" or something like that. Raw, savage, but still subtler than outright spelling it out.

A sacrifice is more for a draw back. Like I take a heavier Ax which strikes harder in sacrifice of speed and tires out faster. It's true that its been done in the past. In my understanding it would be more called a "gift to the gods" a present. But I also would expect a priest to twist words.

Aztecs? You capture enemy soldiers or civilians and offer them to whatever pagan God you worship.. Come on...we literally have the tech called "Slaves".