I was browsing Elanthipedia and noticed this on the sacrifice command page: Animal is supported, but the sacrificial animals have not been introduced yet.
As a sacrificer enthusiast, I'm intrigued. There shouldn't be a problem finding suitable subjects now. I mean, just look at all these little piggies running around after the fest. I doubt people would mind too much if a few of them went to the Dark Gods. Drogor likes bacon, too.
Seriously, though, I'd love to see this implemented. Sacrifice is one of my favorite rituals and it would be nice to have a command that can be used a little more reliably than the other two.
