Several maids enter the room with buckets of blood, the smell of each bucket is different and they all have a great smell showing the quality, I think around 40% is human and the rest is from different races.
'Is this...mermaid blood? How?' Mermaids can't be killed outside of water or everyone in the area gets a curse that makes any sea creature attack that person.
"Curious? My darling undead, the mermaid blood was obtained by killing them in the water and then extracting it, we created a 'breeding ground' where we raise various races from babies to the perfect stage for slaughter."
'Like animals...' She just said that she basically made a breeding and slaughterhouse using the races to obtain blood, she really has 0 morals, I guess she just didn't exterminate any race so as not to lose food.
"Grimm, why this blood tradition?" The books don't explain well why when vampires get married on the first night they must have relations in the middle of blood.