There was a assassin restaurant\Ball were only Assassin's could come to to eat dance or just chill, the restaurant was runned by the famous Akabane assassin family but no one actually seen there face all the Assassin's there wore ball masks to hide their identity, the zoldyck family walked in to get some food as they looked around the 4 story expensive looking place as a butler welcomed them

Butler: Hello do you guys have a reservation pass card?